ctrl-click in the camera image to move the head
Merges Johannes’ change which allows the user to position the camera by clicking the mouse.
Merge is made with some modifications:
Shift is used instead of Ctrl as Ctrl is the popup modifier on Mac and Windows.
Move is made at Safe-Z.
Move is made using MachinePanel job queue.
Reverses the change of adding the offsets to the Camera, as this would break a great number of things.
Fixes a few leftover bugs in the GrblDriver.
Merge branch 'develop' into add-functional-testing

* develop:
  Fixes a few leftover bugs in the GrblDriver.
  Merges Johannes’ change which allows the user to position the camera by clicking the mouse. Merge is made with some modifications: Shift is used instead of Ctrl as Ctrl is the popup modifier on Mac and Windows. Move is made at Safe-Z. Move is made using MachinePanel job queue. Reverses the change of adding the offsets to the Camera, as this would break a great number of things.
  ctrl-click in the camera image to move the head