Begin nominal CLI support.

We need a tool to snoop the event stream coming from a change coprocessor.  We'll then use it to write an integration test.
SniffCommand connects to an hbase coprocessor and prints events.

Since it needs the hadoop stack to run, by far the easiest way to run it is to have the big jar in hbase's lib directory, and then run

hbase meerkat sniff
Have a starting printout, just to know it's alive.
Put a trailing space on topic names to prevent unintented matches.

Now events for table 't2' won't be dispatched to subscribers for table 't'..