scripts/gateone.conf (Upstart script):  Removed the hard-coded '--pid_file' from the 'exec gateone' line.  It's not necessary since Upstart does its own PID tracking.
core/utils.py:  Added a `logging.error()` message to `write_pid()` that gets called when the PID file could not be written (e.g. permissions problem).  This should prevent the situation where Gate One won't start via init script(s) but there's no indication as to why in the logs.
core/server.py:  Added some better error reporting in the event that some other process is already using the address:port combination that Gate One is configured to use or if the user does not have permission to listen on that address:port combo.
terminal/logviewer.py:  Fixed a bug where HTML playback files were not rendering properly due to a bad path to the 256colors.json file.