Make vboot_reference build in MSVC command line environment.

This is a mostly NOOP change which modifies the source code
to compile cleanly in the MSVC command line build
environment.

A new makefile is introduced (msc/nmakefile) along with a
README.txt in the same directory explaining how to build
the code in the DOS window. As of this submission the build
is running in a 32 bit environment, the intention is to use
the same makefile for 64 bit builds in the future.

Enabling high compilation warnings level allowed to
identify a couple of bugs in the code which are being fixed.

Not all sources are being compiled in the MSVC environment,
only those in firmware/ and most of those in test/
subdirectories. The benchmark calculations require porting
of the timer facilities and are being postponed.

TEST

Built in DOS and linux environments. Ran unit tests in
linux environment.

Review URL: http://codereview.chromium.org/2809037
diff --git a/firmware/lib/vboot_kernel.c b/firmware/lib/vboot_kernel.c
index e6658d7..17cd925 100644
--- a/firmware/lib/vboot_kernel.c
+++ b/firmware/lib/vboot_kernel.c
@@ -108,6 +108,8 @@
   return 0;
 }
 
+/* disable MSVC warning on const logical expression (as in } while(0);) */
+__pragma(warning(disable: 4127))
 
 int LoadKernel(LoadKernelParams* params) {