big refactoring of visual studio projects, started using nuget

vsprojects/third_party/openssl/OpenSSL.mak

vsprojects/third_party/openssl/buildinf.h

vsprojects/third_party/openssl/opensslconf.h

vsprojects/vs2010/build_openssl_x86.bat

vsprojects/vs2010/global.props

vsprojects/vs2010/gpr.vcxproj

vsprojects/vs2010/gpr.vcxproj.filters

vsprojects/vs2010/gpr_test_util.vcxproj

vsprojects/vs2010/grpc++.vcxproj

vsprojects/vs2010/grpc_csharp_ext.vcxproj

vsprojects/vs2010/grpc_csharp_ext_shared.vcxproj

vsprojects/vs2010/ssl.props

vsprojects/vs2010/third_party/zlibvc.vcxproj

vsprojects/vs2013/build_openssl_x86.bat

vsprojects/vs2013/grpc++.vcxproj.filters

vsprojects/vs2013/grpc.sln

vsprojects/vs2013/grpc_csharp_ext.vcxproj

vsprojects/vs2013/ssl.props

vsprojects/vs2013/third_party/zlibvc.vcxproj

vsprojects/vs2013/winsock.props