I searched and replaced all molecular_weight and replaced them with molecular_mass
updating comments
updating comments and adding back liscense.txt
added base tape9 and cache.load() optimization which makes the cli run in a minute, rather than an hour.
alost there
first-cut origen transmuter
Origen runs, but segfaults
added more sensible default values
origen fails with read error
Initial add of ssw_combine.py example
origen transmuter works...but not with base_tape9.inp
lost roundtripability of writing in favor of robustness
Minor style fixes.
Merge branch 'staging' into o2t
updated chainsolve
fixed docstrings
updated copywrite
fixed more incorrect usages of name molecular weight
Add nds fission product yield to nuc_data
Add basic docs to ndsfpy