Sample client

[SrimantaBarua]

Since the terminal-based client has already had some work, let's continue with that. It will give us a good platform to test the backend. @v-superuser might have features he's planned for it.

• Handle SIGWINCH for window resize, instead of querying each time ( Handle SIGWINCH for resize #5 )
• Asynchronous input instead of polling ( Asynchronous everywhere #8 )
• Communication protocol ( Communication protocol #7 )