Upgrade to clojure.java.jdbc 0.3.0

This is a stopgap; we're still using the old, deprecated API. The only
change is to point to said API at its new name in 0.3.0.
Merge pull request #18 from aperiodic/jdbc-0.3.0

Stopgap solution for clojure.java.jdbc 0.3.0 support