Add Start, Stop, Pause, Unpause, Suspend, & Resume

Fixes #190.

These six functions, of which Start and Stop are undocumented on
OpenStack's API reference, should facilitate an easier method to place a
server into a suspended-animation state.

Pausing a server will cease its operation, but will hold its state in
the hypervisor's RAM.  Suspending a server will cease the operation and
write the results to disk or other non-volatile medium.  No idea
what-so-ever what Stop does.  Use Stop at your own risk.