Fix segment counts in the rotation gizmo

[xDUDSSx]

These issues are apparent when halfCircleSegmentCount is a low value like 8.

1. When drawing a full circle the actual segment count used was halfCircleSegmentCount when it should be double that. That also caused it to loop onto itself once making it a little bolder that it should be.
2. The active rotation indicator was missing its last segment, making it a little shorter than it should be, not noticable with a high segment count but when the segment count is low it stops following the mouse properly.

I'm working on some improvements to the rotation gizmo and noticed these issues along the way.

[xDUDSSx]

Here's a picture demonstrating the issue. I've marked in red where my mouse actually was. The half circle indicator stopped short. Also in the same picture it's visible that the indicator half circle has the same amount of segments (well minus the missing one) as the rotation axis circle while its segment count should be half of that. Or rather the axis circle should have twice as many.

[CedricGuillemet]

Thanks!