Add collision polygons

Rather than using the entitie's height and width for collision, add
unique collision polygons for each entity
Add z-indexes. Willie the Gnome shall always be drawn over things...

Conflicts:

	coffee/components.coffee
Merge branch 'Purest'
Update collision repulsion code to handle collision polygons
Change easing magic number to less than that which it had been
Update collision polygons for buildings
Add a Border building
Increase taterGit distance!
Make the z-index dynamic based on y
Merge branch 'Purest'