Naive first implementation of new dirty rectangle tracking
Fix logic error with stale rects
functionally complete dirty_rect rewrite
factor out a rectangle manager
Change name of newrect to currentrect
Remove cruft from old code
Remove cruft from canvas.js
Improve docs a bit
Add debug mode, and fix error in merge code
Rename merge->mergeSet and simplify so that it works in place.
Optimize order in which entities are drawn
Optimize mergeset algo
Remove extraneous flag and console debug
Fix follow and timer tests
Merge branch 'selectMaster' of https://github.com/starwed/Crafty into starwed-selectMaster

Conflicts:
	src/text.js
Merge branch 'dirty_develop' of https://github.com/starwed/Crafty into starwed-dirty_develop

Conflicts:
	src/canvas.js
Merge pull request #468 from starwed/test-fixes

Fix follow and timer tests
Merge branch 'develop' of https://github.com/craftyjs/Crafty