Descriptive PSA6C entries

[stheroux]

From a beta-tester: "PSA6C is populated with text values (e.g., Chaparral, Central Valley) rather than abbreviations (e.g., CH, CV) when coming out of Tyler's tool. I suggest adding the text values to your crosswalk or conversion table so XerMtn can handle both options since there will be historic and future metrics calculated."

NC==North Coast
DM==Deserts Modoc
CH==Chaparral
CV==Central Valley
SC==South Coast
SN==Sierra Nevada