Compute areas. Associate host/hosted

Added in script :

• Find and store coplanar boundary in a space
• Find hosted boundary and store relation between host/hosted

New functions :

• get_plane
• is_coplanar
• append

Class modifications :

• RelSpaceBoundary :
  • Refactor
  • Inherit from Root
  • Moved as much as possible property init in init
• Root : Base class for boundary and elements
• Element : Generic simplified class for windows / door slabs / etc…