Selected-element buttons were going nuts when an element attribute changed.  Fixed now.
Buttons operating on the selected element now enable/disable, instead of appear/disappear.
Element floating was sped up slightly.
Lines are now selectable.  (Thought this will take some non-trivial refactoring to work perfectly.)
Merge branch 'master' of https://github.com/borkabrak/stijlus

Conflicts:
	draw.js