Added a few more missing files and re-generated project files.

Makefile

build.json

vsprojects/vs2013/gpr.vcxproj

vsprojects/vs2013/gpr.vcxproj.filters

vsprojects/vs2013/gpr_shared.vcxproj

vsprojects/vs2013/gpr_shared.vcxproj.filters

vsprojects/vs2013/grpc.vcxproj

vsprojects/vs2013/grpc.vcxproj.filters

vsprojects/vs2013/grpc_shared.vcxproj

vsprojects/vs2013/grpc_shared.vcxproj.filters

vsprojects/vs2013/grpc_unsecure.vcxproj

vsprojects/vs2013/grpc_unsecure.vcxproj.filters