Update Windows build files to Visual Studio 2015, add x64 platform, and adjust for libsrtp 2.0.x changes.

(These project files should work on older Visual Studio versions back to Visual Studio 2010 with minor adjustments.)
diff --git a/srtp2.vcxproj.filters b/srtp2.vcxproj.filters
new file mode 100644
index 0000000..6daa0d9
--- /dev/null
+++ b/srtp2.vcxproj.filters
@@ -0,0 +1,186 @@
+<?xml version="1.0" encoding="utf-8"?>
+<Project ToolsVersion="4.0" xmlns="http://schemas.microsoft.com/developer/msbuild/2003">
+  <ItemGroup>
+    <Filter Include="Source Files">
+      <UniqueIdentifier>{4FC737F1-C7A5-4376-A066-2A32D752A2FF}</UniqueIdentifier>
+      <Extensions>cpp;c;cc;cxx;def;odl;idl;hpj;bat;asm;asmx</Extensions>
+    </Filter>
+    <Filter Include="Source Files\Kernel">
+      <UniqueIdentifier>{c23c2703-7a15-4b7e-be1c-0555b7d0f8e1}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="Source Files\Ciphers">
+      <UniqueIdentifier>{43e45f3f-795e-4f2a-8801-3e19b7801d07}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="Source Files\Hashes">
+      <UniqueIdentifier>{11a7bf2a-6706-4c35-8e91-f58bef0f8669}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="Source Files\Replay">
+      <UniqueIdentifier>{237501ce-7043-44c7-a895-df2ceae6c8cd}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="Source Files\Math">
+      <UniqueIdentifier>{2a11592a-e474-4a50-bb3a-e4f039633257}</UniqueIdentifier>
+    </Filter>
+    <Filter Include="Header Files">
+      <UniqueIdentifier>{93995380-89BD-4b04-88EB-625FBE52EBFB}</UniqueIdentifier>
+      <Extensions>h;hpp;hxx;hm;inl;inc;xsd</Extensions>
+    </Filter>
+    <Filter Include="Resource Files">
+      <UniqueIdentifier>{67DA6AB6-F800-4c08-8B7A-83BB121AAD01}</UniqueIdentifier>
+      <Extensions>rc;ico;cur;bmp;dlg;rc2;rct;bin;rgs;gif;jpg;jpeg;jpe;resx;tiff;tif;png;wav</Extensions>
+    </Filter>
+  </ItemGroup>
+  <ItemGroup>
+    <ClCompile Include="srtp\ekt.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="srtp\srtp.c">
+      <Filter>Source Files</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\kernel\alloc.c">
+      <Filter>Source Files\Kernel</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\kernel\crypto_kernel.c">
+      <Filter>Source Files\Kernel</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\kernel\err.c">
+      <Filter>Source Files\Kernel</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\kernel\key.c">
+      <Filter>Source Files\Kernel</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\cipher\aes.c">
+      <Filter>Source Files\Ciphers</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\cipher\aes_icm.c">
+      <Filter>Source Files\Ciphers</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\cipher\cipher.c">
+      <Filter>Source Files\Ciphers</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\cipher\null_cipher.c">
+      <Filter>Source Files\Ciphers</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\hash\auth.c">
+      <Filter>Source Files\Hashes</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\hash\hmac.c">
+      <Filter>Source Files\Hashes</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\hash\null_auth.c">
+      <Filter>Source Files\Hashes</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\hash\sha1.c">
+      <Filter>Source Files\Hashes</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\replay\rdb.c">
+      <Filter>Source Files\Replay</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\replay\rdbx.c">
+      <Filter>Source Files\Replay</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\replay\ut_sim.c">
+      <Filter>Source Files\Replay</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\math\datatypes.c">
+      <Filter>Source Files\Math</Filter>
+    </ClCompile>
+    <ClCompile Include="crypto\math\stat.c">
+      <Filter>Source Files\Math</Filter>
+    </ClCompile>
+  </ItemGroup>
+  <ItemGroup>
+    <ClInclude Include="crypto\include\aes.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\aes_cbc.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\aes_icm.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\alloc.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\auth.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\cipher.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\config.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\crypto.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\crypto_kernel.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\crypto_types.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\cryptoalg.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\datatypes.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="include\ekt.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\err.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\gf2_8.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\hmac.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\integers.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\key.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\null_auth.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\null_cipher.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\prng.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\rand_source.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\rdb.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\rdbx.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\sha1.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="include\srtp.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="include\srtp_priv.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="crypto\include\stat.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+    <ClInclude Include="include\ut_sim.h">
+      <Filter>Header Files</Filter>
+    </ClInclude>
+  </ItemGroup>
+  <ItemGroup>
+    <None Include="config.hw" />
+    <None Include="srtp.def">
+      <Filter>Source Files</Filter>
+    </None>
+  </ItemGroup>
+</Project>
\ No newline at end of file