Enable the validator's 'onlyNotNull' option.

This option has no effect if 'onlyDefined' is set to false.
Cleanup:  Validator plugin internal function name.
Add tests for validator's 'onlyNotNull' switch.
Fix validator 'onlyNotNull' test to use existing table columns.
v0.2.0

* Upgraded `pg`, `mysql`, and `validator`.
* Added a v0.10 build to travis
Merge pull request #69 from doug-martin/master

v0.2.0
Merge pull request #68 from jordan-ayers/topic/validator-options

Topic/validator options
Updated v0.2.0 history and coverage html
Merge pull request #70 from doug-martin/master

Updated v0.2.0 history and coverage html