Make Main class no longer a static class and add support for embedded server

This means that if you start smashbattle in normal mode, an extra thread is started.
In this thread the server will be launched with a special "no_sdl" flag enabled.
This flag will make sure that it doesn't perform drawing etc.

Not everything works properly yet, I think we need to refactor everything that's static into normal classes.
Like Gameplay etc. Main was most of the work.

This is a work in progress, but so far it's pretty difficult to make sure there is no shared state between the threads.
Make Main own the ServerClient and Server instances. Remove statics from Gameplay classes.

Stuff is still very unstable :-(
Remove some more static stuff. Disable the embedded server feature (made configurable).
Make the fix in Server::createSocket depend on the ENABLE_EMBEDDED_SERVER define as well
Fix some warnings
Merge branch 'network_multiplayer' of github.com:DemonTPx/smashbattle into embedded_server

Conflicts:
	Battle/CharacterSelect.cpp
	Battle/ClientSettings.cpp
Merge pull request #60 from rayburgemeestre/embedded_server

Make Main class no longer a static class and add support for embedded server