Added issue 283 to changelog
Issue 292: save state for multiple selection
Save state in functions addToSelection removeFromSelection
Added issue 292 to changelog
Issue 294: handle click on input element in tree
Added issue 294 to changelog
Updated version to 0.21.0
Merge branch 'dev'

Conflicts:
	extra/bower.json
Merge branch 'master' into drag-n-drop-box

Conflicts:
	tree.jquery.js