This patch renames |SocketConsumerBase| to |DataSocket|, and for the
I/O classes |SocketConsumerIO| to |DataSocketIO|. |DataSocketIO| also
contains send and receive functionality from |SocketBaseIO|.
|DataSocket| is a virtual base class that represents a socket that
transfers data, without a particular constraints to what the data
represents. |DataSocketIO| is the corresponding helper class on the
I/O thread.
