Upgrade slider to animate and support touch events.

git-svn-id: http://blockly.googlecode.com/svn/trunk@1706 c400ca83-b69d-9dd7-9705-49c6b8615e23
Speed up getAllBlocksFunction.

git-svn-id: http://blockly.googlecode.com/svn/trunk@1707 c400ca83-b69d-9dd7-9705-49c6b8615e23
Speed up getDescendants and setCollapsed.

git-svn-id: http://blockly.googlecode.com/svn/trunk@1708 c400ca83-b69d-9dd7-9705-49c6b8615e23