Initial version of GUI to manage flows on different clusters.
 New option in abirun.py to cancel the jobs in the queue and SIGKILL the scheduler.
 More tools for controlling flow execution from remote
 Simplify code
 git add GUI code
 Trigger GUI refresh when the database has been modified.
 Assume the user has setup the SSH-Agent on the localhost.
 GUI for converting structure data into several formats.
 More docstrings in fabfile.py
 Use new approach for WX viewers based on mixin classes
 Add menu entry for ncview
 Popup Menu of k-points (info on the little group).
 Minor changes.
 Use new interface for generating Abinit flows (support for command line options).
 Add support for VESTA