SwiftSockets vs CocoaAsyncSockets

[izqui]

Following the discussion in #19.

For the sake of simplicity and some weird errors when building for both platforms, right now I'm making master to be SwiftSockets only and moving the Async Socket + Swift Sockets to the branch multisocket.

As @Danappelxx was saying, SwiftSockets might be more unstable at the moment, but it seems like an easier to work with library and also it will be easier to work with (hopefully) once the OSing of Swift happens.