Get tagging working; refactor schema support.

- git push --tags appears to work now
- Schema is now stored in a var which is evaled to get actual schema.
  That lets us use .hashCode as a convenient way to get a hash of the
  schema so we can reassert it only when it has changed. I'm not sure
  it's going to last, and it does require us to quote database functions
  and use the function and tempid calls instead of the database
  literals, but it does appear to work. It's also better in not
  requiring a JVM restart to pick up schema changes.