utils.py:  Fixed a bug in `get_applications()` where it was setting the directory name to lower case instead of the application name.  This would only cause problems if you were running Gate One out of a directory that had upper case characters (e.g. you just downloaded it and ran it out of that dir).
terminal.js:  Removed "GateOne.Help" from the dependency list at the top.
terminal.py:  Added a missing text rendition:  39 (foreground reset).
terminal.py:  Fixed a bug where the HTML_CACHE wasn't being used when it became empty.
terminal.py:  Fixed a bug where passing `renditions=False` to `Terminal.dump_html()` wasn't working properly (scrollback buffer exception).
go_async.py:  Added a version of `PeriodicCallback()` that works without `tornado.ioloop.IOLoop`.  Basically, it lets you test code that uses PeriodicCallback in an interactive interpreter without having to start the IOLoop (and block as a result).