Send and Recv support

[vimalloc]

We need to be able to send and receive data on the socket concurrently (or similar to that with a non-blocking or asynchronous approach). This is so that we can send pings every so often to check the state of the socket, and so that other people using this as a library could send commands without having to wait for a recv call to happen first (ex, sending a message to a buffer).

Originally, I was planning to simply use try_clone on the socket, and setup 1 thread for receiving and 1 thread for sending. However, apparently this doesn't working ok SSL sockets (see sfackler/rust-openssl#338 and http://stackoverflow.com/questions/14467630). With that out of the question, I think using a non-blocking socket to do both the sends and receives is probably the best way to go.