Refactoring and/or Deprecation of Segment Lofts

[joergbrech]

The overwritten BuildLoft functions of fuselage segments, wing segments and wing component segments make some assumptions regarding the number of faces per segment. These assumptions may be wrong at the presence of guide curves, or after Boolean operations with e.g. control surface cutouts or duct cutouts.

These functions must either be refactored or enterily deprecated. Either choice might have a large impact at different locations in TiGL's source code. If we choose to deprecate these functions, we still need to cache the clean surfaces for the GetPoint functionality.