As the preliminary step for releasing 'api' branch SCM clients code from postreviews is pulled out into rbtools/clients/*. In the future those clients should be merged with ones from 'api', for now it lets us separate theirs code and hence simplify maintaining of 'api' clients up-to-date with master's.

git history is at http://github.com/mbait/rbtools/tree/new-clients

rbtools/tests.py passes all tests except two suspicious which fail on master and perhaps should be reviewed