Fixes download link, general code improvements

* Use a static var for the cache prefix, so we don't have 404's caused by me
	using different strings in different locations (doh).
* Use a config value to store the downlaoded file name. Add the necessary
	Guice/DI infrastructure to handle that.
* Rename Application controller to Main.
* Update Main JS view so the download button now works (Because it does)