sncat.py: changed the setting of model parameters in the mag_getter to
use different syntax. Checked that tests pass.
sncat.py: minor change to the way the output of the getter in vals was
being set, and checked tests pass
Removed redundant if statements since the statements were supposed to
skip items that will be skipped with the current catalog write
statements, and checked that tests are passed
Added understanding_galids.py : to figure out what our unique ids should
be
sncat.py: removed unnecessary commented lines