Made interference function strategies independent of scalar/matrix formalism; this now enables all strategies to be used with polarization

Fixed some problems with ambient material not being initialized in diffuse form factors; added the final part of diffuse calculation for polarized mesocrystals

Fixed bugs in: Refactor: pulled dwba decoration of form factors out of LayerStrategyBuilder and into global function

Refactor: pulled dwba decoration of form factors out of LayerStrategyBuilder and into global function