Customized the search box area to look more like designer mockups.

Used a table view and text field rather than UISearchDisplayController
to give us more customization freedom. Many small interface tweaks.
Improved search term highlighting and fixed related crashes. Loads
first section of article initially, then remaining section.
Much snappier.

Change-Id: Ie19f24e99e4a21b94b50d92e4851afbb73f0db6e