This allows to type in numinput 720 and indeed get a rotation of 720°, not 0°...
This patch has been painful to come with... It basically applies 'big rotations' in steps < 180°, such that compatible rotation works as expected. This implies resetting current rotation to initial one first, otherwise we'd end up applying much more turns than expected when that code is called more than once.
It also makes things somewhat slower for big rotations (millions of degrees), maybe we should add a safeguard?
And since that's a case that cannot happen with regular tool/widget-driven rotation, it's only enabled when numinput is used for now.