Blender Git Loki

Bugfix #28734

Double clicks were never working reliably in Blender - this mostly because
it wasn't a real event, but something generated in the handler code.

Now it is an actual event - meaning it always gets handled (if you have
a keymap item for it of course), but if there's no doubleclick handling
it treats the doubleclick as a normal click.

Also cleaned code. No recursion anymore.