Transform Tool plugin

@Coverop thank you for feedback!

Some critical bugs were found:

  1. Crash on sequencer save, when mode is active
  2. Sequencer autokey not working with rotation handles
  3. Mode tab priority not set
  4. Default editor gizmo size adjustment not considered

All of this is fixed now and pushed to marketplace! Update will be available through launcher in a couple of weeks.

Also, guys, feel free to ask new stuff to add!

Cheers