Remove read-in data modules, from ext file

- read-in modules for isochrones and photometry saved in mywrangle.py
- these modules have been deleted from main.py (in branch "testing")
- testing whether this works, and how merging process works on git.
MODULE: mywrangle.py

- Imported all read-in modules into mywrangle.py, to be called
from main.py using from mywrangle import *

- within read_phot() module had a reference to dsph_select, an
external variable not defined in read_phot(). Previously this
problem was undetected b/c dsph_select was in global namespace
in main.py. Fixed: dsph_select-->photfile.