Prototype swords

Creates the very basic beginnings of a sword system. SwordMover handles moving a sword blueprint following the mouse, with some tweakable dynamic movement (see here for more info: https://www.youtube.com/watch?v=KPoeNZZ6H4s).

The 'sword' also leaves a temporary trail of objects when it is swung hard enough, which will eventually be usable to block with.

Also includes a bunch of Unreal generated stuff to get everything set up, including a (very large) initial level (sorry).