Updates include:
- Added backward compatibility for isochrone file names created
before v2.3 - When reading isochrone from existing file, only keep user
requested filters in resulting table. - Changed the global random seed to a random generator within each class,
but still retaining the reproducibility. Test cluster files in
test_data also updated accordingly for testing purposes - Added filter support for IRTF L-band
- Added conversion function between ST mags and Vega mags