Basic socket IO and application handling

This release introduces a PeerSocket class for asynchronous reading and writing to a socket, a MessageRouter to forward incoming messages to a registered application or drop it, and an interface for applications that want to use the library.

Users would set up a MessageRouter instance which activates socket IO, and register an IApplication implementer to it. When a message arrives for the specified protocolID, the applications OnMessageReceived method is called with the message as parameter for further inspection.