Initial checkin of python client

It doesn't work reliably yet, but its enough progress that I don't want to
lose it by accident.
Fix compiler warning flagged as error

On pod 11, we saw the following error:

cc1: warnings being treated as errors
src/base/target_offset_table.c: In function 'tot_init':
src/base/target_offset_table.c:26: error: 'rc' may be used uninitialized in this function

This patch initializes rc to 0 to avoid this error.
XDD Python now has RMI over tunnelled SSH

In order to build the XDD python client's mgmt functions,
we now forward Pyro rmi's over a Paramiko based SSH
tunnel.  This is the major step in converting XDDCP to use
python rather than shell scripting.
Improvements to testing

A bunch of stuff to perform better unit testing.  This especially
adds testing of the new Python code.
Merge branch 'master' of https://github.com/bws/xdd