Merged requested to merge Velociraptor_output_strategy into master
- Write the groupIDs returned by VELOCIraptor to the SWIFT snapshots.
- Add an option to run VELOCIraptor every time a snapshot is written irrespective of the STF strategy.
- Measure the time spent in VELOCIraptor in a SWIFT way to be correct in the global accounting.
- Fix the units used by VELOCIraptor.
- Fix the cosmology used by VELOCIraptor.
- Add temperature to the data passed to VELOCIraptor.
- Add the stars to the data passed to VELOCIraptor.