edit mode handling.  Allows retopo multiple retopo sessions (even on different original form

objects) to always push new generated geom into same retopo object
Merge branch 'dev' into feature/editmode
allow hover existing non manifold edges in edit mode
remove prints, put update code in draw since that reset's self.last_matrix.  If performance is slow

can cache a separate self.last_visible_matrix to only update when mouse moving at the end
of navigation one time, instead of each redraw during navigation.
Merge branch 'feature/editmode' into dev

Conflicts:
	__init__.py
fix for editmode use with new temporary object for high res or modified mesh