Improve coded_stream.h handling on MSVC.  Avoid a bogus runtime check and enable little-endian optimization.  Based on patch from Nathan McDaniel.
Improve coded_stream.h handling on MSVC.  Avoid a bogus runtime check and enable little-endian optimization.  Based on patch from Nathan McDaniel.

git-svn-id: 54a00c96d7caad0f188abf6e0ebede48f6547068@325 630680e5-0e50-0410-840e-4b1c322b438d

tdfischer/protobuf,tdfischer/protobuf,tdfischer/protobuf,tdfischer/protobuf,tdfischer/protobuf