Adds Column Date click events.

Adds support for the following events on column dates:

- on-column-date-clicked
- on-column-date-dbl-clicked
- on-column-date-context-clicked

Also updates demo & readme to reflect new events.
Updates src file. Corrects readme typo & jshint errors.
Merge pull request #81 from ericthelast/feature/add-column-date-click-events

Adds Column Date click events.