Added resource installation - closes #1

The launcher will now access an instance of a
resource installer to download the vanilla game assets.
Additional changes include the adding of a constant variable
and the addition of an XML utilities class.

Signed-off-by: Tristen Allen <spyboticsguy@gmail.com>
Updated formatting on the assets pull request

Signed-off-by: Dalton Pelc <daltonjpelc@gmail.com>