Wrote fucntion, print_lytaf_event_types(), to print out the different
event flags in each of the LYTAF databases.
Changed default of artifacts kwarg for remove_artifacts_from_lyralightcurve()
and _remove_lyra_artifacts() from "All" to [], i.e no artifacts removed.
This is because a user will never want to remove all arifacts and should
think about which he/she wants to remove rather than blindly removing
all of them.