Update RATS-software.json

PNCC external link looks like it's the public code repo...? Same with PMCES? gbfb software external link looks like a paper citation? Same with mlp_gbfb? MHEC and COMBO software external links point to published papers. Several unnamed entries, one of which (by LDC team under categories scripts for conditioning) has a malformed internal link, external link, public code repo, and description.
Merge pull request #22 from tmycann/patch-21

Update RATS-software.json