Causes simCluster to output photometry files
Removes invalid assertion from logPriorMass() in densities.cpp
Fixes vtable/typeinfo issue in WdAtmosphereModel

Partially duplicates the same process which was undertaken using the new GenericMsModel for the MsRgbModels. Long story short, InvalidModels don't work properly if the parent class implements things which they need to override.
Various performance tweaks

Various profiling-/benchmark-based speed performance tweaks which should cause significant speed increases (particularly for --noBinaries runs).