Populate the master_finders table.

This commit allows the master finders table to take delta coordinates. Closes #23

ephem/ephem.py
    - Changed the name of the main module from `ephem` to `ephem_main` to avoid confusion.
    - Added an assert get_header_info to ensure that fits files are used.

ephem/run_ephem.py
    - Changed the referenced from main to ephem_main.
    - Changed the wildcard import from ephem to ephem_main.
    - Changed the connection string to use the pymysql driver.
    - Added code to allow the MasterFinders class instance to correctly populate the master_images_id foreign key.