add methods to grid.py:

rename_grid_variable
update_grid_variable
clean

add functions to functions.py:

convfloat
datalinedict
pad_output_distribution

Fixed some complaints that pylint had and fixed a correct mass ratio lower bound in the interpolators

Working on the M&S grid now: added alot of verbose output, and making sure all the interpolators are freed. Now I need to add the eccentricity as options and output for plots. Also reformatted