Issue 62 menu drag open

Fixes #62 

Dragging anywhere on the `#main` pane can open the menu.

I have tested it on my HTC (the lowest powered device I own) and it seems fine, but not perfectly smooth. I guess that was too much to ask for.

If it's too bad, maybe it can be a 4.x+ feature (since all 2.3 devices have menu buttons)?