Another keymap goodie for test fun: Tweak events allow to be limited
to a direction, like North, South-West, etc.
Tested with View3D keymap for border, circle & lasso. Issue to look at
still is whether a border should start immediate, or first draw a cross...
this can be an operator property of course.
Note that tweak code can be extended to corner-gestures too (so you can
do a north+east, north+west, and so on... nice for later).
Time to get keymap saving work! :)
(Fixed bug in Mesh edit circle select, missing notifier)
d5c990664e