core/utils.py:  Added a helpful message to `killall()` to indicate that it's running and what it is doing.
scripts/init/gateone-debian.sh:  Changed the comment at the top to indicate it should start on runlevel 2 by default.
setup.py:  Modified the systemd installation variables so that they are more descriptive (instead of just re-using the upstart variables).
core/server.py:  Fixed a bug where Gate One could get stuck in an exception loop if a theme file was removed from the cache (by something other than Gate One).