Upgrade to korma 0.3.0-beta13.

Allows not to use c3p0 without hacks.
Lib upgrades
Replace clj-json with cheshire. Pretty print JSON.

Fixes #71, fixes #64.
Better handling for number of returned results.

Added configuration parameters :default-max-search-results and :allowed-max-search-results.
Rename parameter pretty-print -> prettyPrint.
parse-decimal accepts integer, float, BigDecimal