Allow multibrush to use an angled axis and have an option to show the axis

This feature allows multibrush to function with an axis that is rotated:
this means for the mirror mode it will use the rotated axis to mirror
over. Additionally a checkbox is added to allow the user to display the
axis being used for mirroring, symmetry and translation.

Awesome patch by Michael Martini. Thanks!

BUG: 327286
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