Add OpenStates districts as mapping IDs.
Fix up a few bad generated IDs.
Adjusting sc's districts.
PR/DC: Add state mapping for at-large district.
SC: Update hd-* => *
-county-no- => _ in nh
dc sldu => ward
PR: roman numeral => digit
MN: leading zero
MA: First pass. Many - => _
MA: Random string fixes.
MA: Remaining IDs
VT: grand-isle => grand_isle
Add aliases for DC and PR.
Build OSIDs into US csv