Bastion: Adding sticky headers and table body scrolling.

The browser does not make scrolling the body of a table easy when
the table is using responsive based styling. The strategy used here
provides two table heads, one of which is treated as a shadow table head
and the other as the true table head. The shadow table head must exist
to get the styling and centering of table headers with the data correct.
A directive is provided to handle dealing with browser resizes to set
the width and height properly.
Bastion: Moving JS tests to be test/feature.
Bastion: Adding docular documentation generator.
Bastion: Updating module names to Bastion.
Bastion: adding user-sessions controller and tests.
Bastion: moving katello constants/global variables into single module.
Merge pull request #2525 from waldenraines/bastion

Bastion: merging master into bastion
Merge pull request #2517 from waldenraines/bastion-user-sessions

Bastion: adding user-sessions controller and tests.
Merge pull request #2477 from ehelms/bastion

Bastion: Adding sticky headers and table body scrolling.
Bastion: Adding data structures for table entities to support show/hide and collapse.
Bastion: collapsing table based on state.