Utilize SimpleWindowListener and SimpleInputListener in pixl
Merge branch 'networking-redux-deux'

Conflicts:
	README
GUI manages its own input -- no longer delegates to pixl.FrFrame
Removes WindowListener methods
Expose InputHandler from GUI. Cleanup
Convert location axes to doubles
Removes comments and bi-cardinal directions
Entity.xr -> Entity.width; Entity.yr -> length
Speed now maintained by Mobs, not Entities
Fixes Knockback; Simplifies Movement; use dx over xa where appropriate
Clarity on tick speed & Knockback fixes
Further cleans Knockback
Ripped out Movement
No idea. Totally forgot.
sauce.
Jumping works again. No collisions. Moved around some packages.
Sprite facing restored
Z-Axis: Adds Entity unit tests and Entity location refactors
z-axis: Fixes collision detection issue by simplifying Entity's facing
direction, width, and height.
z-axis: Cleaning comments