Table outlining support in the editor

Feature file editor support for table outlining. Helpful to reduce vertical space used when a test has long tables.

The collapsed view is the table header and the tool-tip is the header and row count::

![Table Outlining Example](http://i.imgur.com/6wPKF.png)

This works with Scenario, Scenario Outline, and Background. Fortunately, support for listening to the outlining configuration option came for free.

This is a re-submit of #243.