Merge pull request #80 from rayburgemeestre/network_multiplayer

Make sure that the draw functions do not draw in no_sdl mode
Merge pull request #81 from rayburgemeestre/network_multiplayer

Forgot to commit the Drawable interfaces
Updated VC project file
Merge pull request #82 from rayburgemeestre/network_multiplayer

Deny clients if there are already 4 connections
Merge pull request #83 from rayburgemeestre/network_multiplayer

Make the server restart again properly
Merge pull request #84 from rayburgemeestre/network_multiplayer

Small fixes
Merge pull request #85 from rayburgemeestre/network_multiplayer

Do not attempt to do anything with audio in non_sdl mode.
Merge pull request #86 from rayburgemeestre/network_multiplayer

Fix "FATAL SDLNet_TCP_Send: There are 0 joysticks available"
keyboard_enabled should always be true after all