Fix GameStarterKit.Mac build error.

[giginet]

I tried to build Samples/GameStarterKit on MonoMac. But it occured build error. I fixed build error. It was checked work correctly on master or v1.1.

• Modify references of Lidgren.Network and MonoGame.framework to in submodule
• Replace invalid classes to new one.

[totallyeviljake]

Thanks!