gateone.py:  Added some fixes to prevent non-options like combine_js from ending up in the auto-generated settings/10server.conf.  Just keeps things tidy and prevents confusion.  It wouldn't hurt anything to have them in the file (in case you've already got them in your 10server.conf, don't worry about it).
gateone.py:  Fixed a bug where you could get an exception with the 'api_keys' setting.  This should correct the problem reported in #226.
gateone.py:  Fixed a bug where users were being sent client-side plugins that had been disabled globally via the 'enabled_plugins' setting.
gateone.js:  Fixed a bug in GateOne.Utils.isVisible() that could cause a NS_ERROR_XPC_BAD_CONVERT_JS exception in Firefox.