Draft Trimex

Description
This tool trims/cuts and extends lines and polylines, and extrudes faces.

Usage

 * trimming or extending is decided automatically from the position of your mouse
 * if you move the mouse cursor over another object, the trim/extend operation will snap to that object or segment
 * pressing will constrain you to the segment currently being trimmed or extended
 * pressing will invert the order of the trimming
 * chamfer & fillet are still not supported but planned
 * When the selected object is a face, or a face is selected from an existing object, the trimex tool switches to extrude mode. In extrude mode, pressing constrains the extrusion to the face normal.