Attempts to fix dragging issues when one surface is over another. Turns off all LayoutViews' draginator subscriptions to their respective surfaces except for the one that is being dragged, resubscribing when dragging ends.
Adds flexible layout generator button
Adds new generated flexible layout code. Adds event arbiter and filter.
Fixes over-surface dragging issue. Removes filter and arbiter.
Merge pull request #72 from kayvon/master

Bug fixes