Photon Source Sampling: Parameters when not using 'gammas' approach

[erelson]

The gammas file currently serves in part to toggle options such as the sampling approach to use, void rejection approach, and debugging. The other purpose of this file is to store photon source information, but this is being removed in favor of reading the MOAB mesh directly. The 'gammas' file can probably be removed completely, in favor of the mesh.

However, the parameters on the mesh must be easy to check and easy to change. A tool(s) for this probably doesn't exist currently. A possible form of such a tool would be like the install script that is included with DAGMCNP.

[erelson]

After typing the below, realized that it does not solve #41, since we need to know what mesh file to read information in this form from... Thus implementing an r2s.cfg parser is probably a preferable option.

Current line of thinking is to develop a new script that uses the contents of r2s.cfg to tag the root set of the MOAB mesh. This script would be called as part of r2s_step2.py, but also would be callable by itself so as to quickly toggle settings. It will include a "list currently tagged settings" capability as well.

Tasks:

• Tagging script that reads r2s.cfg parameters
• Add tagging script into r2s_step2.py
• source.F90 additions to read parameters