Fixing error with relative energies

An error resulted from not using relative energy data points. No matter
what, calculate.py used to create a list of these energy data points
and try to find its minimum. Finding a minimum of an empty list results
in an error. Fixed by adding a conditional statement.

Added more to evaluate.py. evaluate.py now can create a file similar to
the par.tot file that was generated by NR_CalcAll.py in Elaine's code.
This can be used to check the alignment of the data and relative
energies between the reference and FF calculated data.
Relative energies should be fixed

Had to make minor changes to to calculate.calculate_x2 because
it had incorrect references. Improved output of evaluate.py.