Blender Git Loki

Changes to the "join area" operator.

This is a patch by Michael Fox (mfoxdogg) that make more
easy join two are, just RMB+Alt in the "origin" area,
drag the mouse to the "target" area and release the mouse.

Note that this is not a "final mouse-bind" for the join
operator, just an easy and simple option for test in
this early stage of 2.5.

Other note: maybe it's a good idea add azones here ?