- updated boolean operation operations:
 * internal restructuring
 * modified api

- removed useless clone() call in import operation
- slight tweaks to attributeChange operation
- updated boolean operations of shape3d to match subtraction:
 * geometry regeneration now done correctly
 * position , scale, rotation now copied over correctly to new instance
 * minor related cleanups
- cleaned up boolean operations calls
- removed bad name assignement in external geometry/ parts imports
- renamed erroneous sourceElement attributes to sourceShape
- minor cleanups
- added generation of code for imports
- added debouncing when setting properties to avoid propertyChange spam