Summary of changes:
- A tri polygon detection and creation option is add to the dot system in the Draw Mesh tool. The operations are the same as those for quads. Just the hotkey it uses is Caps-Lock.
- A hotkey "Shift+Alt" is added for the "Extrude" sub tool in Draw Mesh tool. This eliminates the need to enable edge-snapping manually in order to activate "Extrude".
- Dynamic mesh can be extruded from corner vertex in "Extrude" sub tool in Draw Mesh tool. Read the tool tip for detail.
- Some bug fixings.