BIM-Tools for Sketchup 0.14.0

Better openings, speed and stability improvements

• openings(cutting components) now still cut holes when overlapping and on/over the face edges
• Speed improvements by replacing individual "add_face" calls with "fill_from_mesh"
• Stability improvements because of better use of observers.
• Removed the GUID field from the menu because it doesn't match the IFC export GUID
• fix side-faces normal direction in openings