Documentation Sprint -- Needs Review

The purpose of this pull request is to significantly improve the documentation of this project. This pull request will be ready to merge when the following has been completed:

- [x] Add [jsdoc](http://usejsdoc.org/) to all app-specific js classes, methods, and properties.
- [x] Add *docs* directory with a README.
- [x] Add instructions to the README on how to setup, run, and document with jsdoc for this project. That includes a minimal style/tag guide.
- [x] Add a jsdoc conf for running the tool from the command line without having to remember all the options.
- [x] Update the git ignore to ignore the output of jsdoc.
- [x] Add an OVERVIEW to the *docs* directory with a high-level description of the project (layout, structure, etc). This is not intended to be comprehensive, just contain enough information to point a developer in the right direction.

@jazahn Can you review this when you get a chance? There's probably too much to cover here, so maybe pick a few things to look at? Let me know if you have any questions.