Blender Git Loki

Modifications to the view3d.select() operator:

1. Two new boolean options have been added to the operator: "deselect"
and "toggle".
2. The previous behavior of "extend" (toggling the selection) has
been moved to the "toggle" option.
3. "extend" now only extends the selection, it never deselects.
4. "deselect" is pretty self-explanatory: it deselects (i.e. opposite
of extend).
5. The built-in keymap has been changed to use "toggle" where
"extend" was used before for this operator, to maintain the
previous behavior in the default keymap.

In short, this works towards making "extend" and "deselect" fully
consistent across all selection tools (adding to and removing from
selection, respectively), but still preserves the old behavior
as well.

(Patch reviewed by Brecht.)