Changed to run the launch command on a separate thread.
Changed to run the launch command on a separate thread.

Changed
=======

* run/launch command now runs in a separate thread so that everyone
  doesn't have to wait for the simulation to complete on the remote
  host.
* run/launch now return a JSON containing info about the simulation
  (uuid, username, hostname).

mcflugen/wmt-rest,mcflugen/wmt-rest