Multiple modifications detailed below:

1. updated module read_phot(photfile):
   -Given an input dsph name, e.g. BooI, it reads-in the CFHT database located in data/CFHT.
   -Fixed bug in data_pd['r0'], A_R is now data_pd['ar'] and not data_pd['ag'].
   -header=None - > header=0, read-in header from top of each database file, names are
    consistent across files

2. updated module read_dsph_data():
   -Added read-in dsph data from mwdwarfs_properties_luis_2.dat, which contains
    additional data such as position, PA, ellipticity, E(B-V).
   -Fixed: in read_csv, added index_col = 0 so that the pandas DF is indexed on
    key='dsph', for both dsphs1 and dsphs2 DFs
   -Delete spurious columns from dsphs2 using del.
   -Added a join between dsphs1 and dsphs2 on key='dsph', since this is the index
    key. DO NOT specify keyword on = ' ', as that is for joining on columns (axis = 1), not
    index/rows (axis=0).

3. updated and tested module likelihood call on main.py:
   - call now has correct number of arguments (5)
   - tested likelihood vs likelihood_matrix, which do same operation.
   - for 2000 stars, likelihood takes 2.5 sec, likelihood_matrix takes 51 sec, so a factor
     of 25x improvement in runtime.
   - note: likelihood() still does NOT include completeness nor LF information.