add moveTo method to elements
implement update chaining via naive method
implement update chaining in memory-efficent way
rename clock example
separate examples
allow external control of stage update/draw
Merge branch 'events' into nested, create nested stage element

Conflicts:
	examples/example.js
	src/stage.js
fix nested stage scaling
add moveTo to clock example
use correct scaling of nested stage
add license
fix debug element outline
merge nested into events
update README and clock example
Merge branch 'master' of github.com:zjmichen/henri
update readme
add canvas focus
constrain key events to focused canvas