Indent mappings table header row
Create bulk editing table header styles

* Prepare table for form and checkboxes
* Switch add button from green to grey
* Add new table styles to style guide
Create selectable and selected row styles

* Style labels and checkboxes to make entire cell clickable
* Add examples to style guide
* Stub actual pages with the expected HTML
* Move padding helper from hits to base
Select table rows with JavaScript

* Toggle row class and checkbox state on selection
* Toggle all when using the header checkbox
* Use indeterminate state in header when only some of the rows are
selected
* Update style guide example
Select groups of rows using shift click

* Use the previously interacted with checkbox and the newly clicked
checkbox to determine the range
* Currently only toggles on
Add form around table posting to edit_multiple mappings
Don't select all mappings when submitting the form

Specify js interaction using class name so that only clicking the
header checkbox toggles table rows.