Get rid of jQuery and its plugins.

[MeanEYE]

We are currently using jQuery in only few places, mostly relying on its DOM element selector which is now readily available in form of document.querySelector. This library is significantly increasing our load time and size for very few usages. The following codes need to be refactored not to rely on jQuery:

• Communicator;
• Language handler;
• Individual module scripts;
• Window system for backend.

[MeanEYE]

Only communicator should be jQuery free for the v0.5 release. It's not realistic to rewrite all of the module scripts without causing major disruption.