Feature: Edit Instruction Tool

[laszlokorte]

A tool for editing the parameters of an instruction interactively on the canvas. Especially for fixing failing instructions.

Eg when using this tool for editing an existing move instruction the distance vector of that instruction should be drawn on the canvas as a dashed line. The one and of the vector should be grabable to edit the move instructions anchor point. The other end should be grabable to edit the distance.

For the rotation and scale instructions the pivot point should be visible on the canvas and dragable to adjust it's position.