brim separated to Brim.cpp,hpp Refactored accessors to PrintObjectPtrs, PrintRegionPtrs, LayerPtrs, SupportLayerPtrs for const correctness.
Ported extension of ExtrusionEntityCollection::flatten() to disable flattening of no_sort() collections.
Reworked the FFF testing framework & ConfigBase::set_deserialize() for more compact tests: set_deserialize() now accepts list of key / value pairs. Fixed an incorrect assert in LayerRegion.