Always divide backing scale factor by 2

This is a bit if a blind change, but it fixes the issues for me.
Previously it was divided by the self.backingscalefactor property,
which would always be 1.

Update the version.

Update version strings

fix: reset margin when reducing the window size

Tag stable-2011.1

Tag stable-2010.2

Tag stable-2010.1

Tag stable-20090825

Tag stable-20081225

Tag stable-20060917