Added AttackCast object used for swinging swords.

AttackCast does a sphere cast from an object's previous position
to its current position and sends hits to all the hit objects.

Outstanding Changes: Ignore the same entity during one attack,
multiple nodes for attacks, ignore parent objects, hit objects
that are initially embedded in the first cast, and possibly
casting to the initial position.
Added IgnoreList to ignore multiple hits against the same objects.

This also adds the root transform, which allows us to always ignore
hits on parent objects.
Added Activation of Attack object to Fighter.
Merge branch 'attack_cast'

Conflicts:
	Assets/Scripts/ProjectScripts/Fighter.cs
Added AttackCaster to Player prefab.