Thrift: C# Bindings.

Summary:
C# generator, library, and MS Build task contributed by imeem.

Reviewed By: mcslee

Test Plan:
Built the Thrift compiler and generated some C# code.
I'd love to say I installed Mono or Portable.NET and built the C# code,
but I did not.

Revert Plan: ok


git-svn-id: https://svn.apache.org/repos/asf/incubator/thrift/trunk@665421 13f79535-47bb-0310-9956-ffa450edef68
diff --git a/compiler/cpp/src/thriftl.ll b/compiler/cpp/src/thriftl.ll
index 0889a12..21a0dd7 100644
--- a/compiler/cpp/src/thriftl.ll
+++ b/compiler/cpp/src/thriftl.ll
@@ -73,6 +73,7 @@
 "cpp_type"           { return tok_cpp_type;             }
 "java_package"       { return tok_java_package;         }
 "cocoa_prefix"       { return tok_cocoa_prefix;         }
+"csharp_namespace"   { return tok_csharp_namespace;     }
 "php_namespace"      { return tok_php_namespace;        }
 "py_module"          { return tok_py_module;            }
 "perl_package"       { return tok_perl_package;         }