Introduces RDAT file format for RNA chemical mapping into Rosetta as well as an app that should reach wide use, rna_predict_chemical_map. First connection of Rosetta 3D modeling to chemical mapping measurements that are widespread in RNA biochemistry, are exploding in throughput, and that are being put on a quantitative footing by our and other labs. This is a merge from rhiju/dms_score before closeout of that branch. No changes in integration tests except a couple that were failing already, and a couple that always seem to change on my mac (match_1n9l & flex_pep_dock).