Fix rack-display for equipment larger than 2Us

 This closes #57
For updater: Assorted cleanups and fixes
Merge pull request #59 from rowanthorpe/improve-update-script

For updater: Assorted cleanups and fixes
Merge pull request #58 from rowanthorpe/fix-handling-equipment-greater-than-2U

Fix rack-display for equipment larger than 2Us
Updates to Apache wsgi file

 * check if _app_path is already in sys.path before appending it

 * switch to maintenance mode when Apache is reloaded and
   _maint_mode == True

 * abstract _app_path and _maint_mode to top of code and label it for
   editing

 * label _maint_file at top of maintenance-specific code for editing (if a
   custom page is being used)

 * in non-maintenance mode there is a _tiny_ added cost of one
   var-assignment and one if-branch during server reload/restart, but
   actual requests have no extra overhead (the "application" function is
   unchanged)

 * update copyright year, and s/ISC/THE AUTHOR/ in copyright notice

 * add commented-out (non-default) version to dynamically handle
   maintenance page changes without server-reloading (but doesn't use
   inotify/etc because doing it portably without sourcing Django libs adds
   too much complexity to be worth it) - for speed-reasons, it uses global
   vars instead of arg-passing