Cleaning up TowerBar.js
More cleanup.
You have to click and drag to place towers now, but it sorta works.
Clean up a bunch of currently unneccesasary changes.
Tower placing works again.
Towerbar is now not redrawn every frame.
Some more significant speedups.
Cache line drawing.
Merge branch 'fast'

Conflicts:
	game/tower.js
	game/towerBar.js