Added runset for photon-transport-like problem (no eps scaling)
Fixed small bug in MAX_IT_accel formulation
Fixed line color issue for no color case.
Fixed minor bug, it_num now neg. if accel. scheme doesn't converge
Added custom function adding ability to data_set.plot()
Fixed plotting bugs for custom function in data_set.plot()

Converted data_object.x and data_object.phi to arrays of floats instead of arrays of strings.
Added diffusion solution to Run 11 plots.
Fixed plot handles (added a comma)
Made some tweaks to make the plots look prettier.

Removed unnecessary markevery line in one of the plot statements.  Rearranged which method gets plotted first.
Modified and finished runsets 5