Updated the 'Edit...' link in the features.
Query down into the WidgetCollection in the features.
Insert an @id on the widget's parent.
Removed the wait_until method that no longer exists.
Click 'Items' more specifically in features.
Correctly location the 'Remove' button.
Use jQuery to find whether the map actually has a feature type.
Use CSS selectors to see which map is displayed.
Use capybara-screenshot.
Include source maps comment in compiled Coffee Script.
Moved some features into unittests.

This was necessary because clicking on "View Public Page" opens a new
browser window, and Capybara doesn't follow the interaction.

Other highlights of this commit:

* Set the coverage element when displaying a coverage;
* Fixed test for KML coverage strings;
* Harden against invalid or missing KML.
Final fixes for Cuke features.

* Changed the item title for one test (duplicate links error);
* Removed failing, invalid test (tested Omeka's admin login page).
Updated Travis configuration.