Updated global_sig to calculate chi-squared. Added module with linear regression.
Added calfiles for two basic arrays, one that inherits from phs and one that inherits from amp.
In global_sig.py I moved file reading to its own file, added a function to fit the global signal with a line through the origin in place of a linear fit. In the test_regress_vary_* functions I added a filter to only plot points with good reduced chi-squared fits.

I put the calfiles, figures, and coeff data in their own folders.

In useful_functions.py I fixed the reduced chi-squared calculation so that it divided by the correct degrees of freedom and I added functions to fit lines through the origin, power laws, and legendre functions.
In global_sig.py I changed the chi restriction to a boolean flag and I changed the functions to accept baselines and coefficients instead of calfiles
Did more fitting