- added prevention of property change if value of property in the given
editor was previously unset
 * this prevents objects "reseting" when initialy selected , or after boolean ops

- added description display as tooltip (question mark)
- added "locking" of fields to prevent accidental editing of values
that are not meant to be edited at a certain point
- minor cleanup all around
- added correct cloning of shape/part properties
- added a constant: shapeDefaultMaxResolution:
 * meant to be used for spheres, cylinders etc
 * would need to be displayed in a special manner in the properties editors
- minor cleanups here and there
- replaced "execute" with "generate" as main method for geometry/shape generation
- replaced call to new class (templatized) instance's "execute" method
with "generate"