Use json type for the args column if json is available.

Also add some constraints to the q_name and method columns.
Merge pull request #136 from joevandyk/json

Use json type for the args column if json is available.
Bugfix: misspelling of word functions in tasks
Merge pull request #154 from tmock12/patch-1

Bugfix: misspelling of word functions in tasks
fix `QC::Conn#connect` when url has no host.

This is the case for the default url when running the tests:

        postgres:///queue_classic_test
Merge pull request #156 from ryandotsmith/fix_connect_for_url_without_host

fix `QC::Conn#connect` when url has no host.
Change log to report time elapsedin milliseconds