Manual (Keyboard) Entry for Modifiers

When I was originally working on the framework for modifiers, I made some good progress with manual entry with a keyboard. This is useful because when you are handling the modifier with the mouse, you can see visually what's going on, but you may not be very precise. For instance, let's say you want to rotate something 45 degrees. With the mouse, you can rotate it until it looks about right, but you might be off by several degrees. With manual entry, a dialog pops up that allows you to type in specific values for the parameters, with zero error. I had some strange bugs in it that made it useless when the original modifier stuff was done, but now I've gone back and fixed the problems that it was having originally, and the manual input system works like a charm. Press TAB to activate it.