run_multi_solver.py is a script that reads in a config file for the
location of the argon_input.h5 files and the chord radius locations and
then runs a multinest solver for Ti and the PCX velocity profile using
all of the images.

plasma.py had functionality added for calculating the momentum diffusion
length, Lnu, using charge exchange cross sections (also added).

argon_plasma_solver.py had minor edits for various functions. The big
change is adding the multi image solver.

check_argon_solver had minor edits for various functions. The big change
is adding the multi image solver check functionality.