Closes #2282:

• The rotation/scaling grip/handle squares should rotate with the layer, not with the viewport. Notice how the layer has a local rotation and the grips use that rotation.
• We want to put a ring in the center that can be dragged to translate the transform cage. This is important for non-filled shapes which have no selection area inside them. In the image below, you'll see the click target in translucent blue. That light blue should appear when it or the solid ring is hovered. (Inside the ring is not a click target though, since it needs to give space for the pivot widget to be draggable.)
• That ring should have local-axis constrained drag arrows. Either side of the arrow (left/right; or up/down) is equivalent. Similar functionality to G X X or G Y Y but without actually being in G/R/S mode and no seeing the number overlays, etc. But we do want an overlay that is just a dashed line through the dragged arrow points going through the entire viewport. It should b either red or green to match the arrow being dragged. Collectively we call the ring and arrows the "compass rose" if you want to use that for your variable names.