Merge pull request #680 from jskeet/aptca

Allow partially-trusted callers again.
diff --git a/csharp/src/Google.Protobuf/Properties/AssemblyInfo.cs b/csharp/src/Google.Protobuf/Properties/AssemblyInfo.cs
index 73a78b0..9a484ad 100644
--- a/csharp/src/Google.Protobuf/Properties/AssemblyInfo.cs
+++ b/csharp/src/Google.Protobuf/Properties/AssemblyInfo.cs
@@ -32,6 +32,7 @@
 

 using System.Reflection;

 using System.Runtime.CompilerServices;

+using System.Security;

 

 // General Information about an assembly is controlled through the following 

 // set of attributes. Change these attribute values to modify the information

@@ -45,6 +46,7 @@
 [assembly: AssemblyCopyright("Copyright ©  2015")]

 [assembly: AssemblyTrademark("")]

 [assembly: AssemblyCulture("")]

+[assembly: AllowPartiallyTrustedCallers]

 

 #if SIGNED

 [assembly: InternalsVisibleTo("Google.Protobuf.Test, PublicKey=" +