Implement a LevelLoader and a barebones Level.
Move the test level into an XML file. Still some work to be done here, but the plumbing is there.
Add docu-comments on the public API for LevelLoader.
Make LevelLoader a static class.
Merge pull request #24 from comp380team3/level-loader

Level Loader implementation
Merge branch 'master' into game-mechanics-newarch

Conflicts:
	PuzzlePathDimension/Game1.cs
	PuzzlePathDimensionContent/PuzzlePathDimensionContent.contentproj