fix(rxApp): hide page titles if not present; Fix #485
Merge pull request #491 from rackerlabs/485-page-title-ng-if

fix(rxApp): hide page titles if not present; Fix #485
fix(rxApp): Have `isActive` compare chunks of URL

This commit also adds an `rx-app-key-{{ item.key }}` class, to help
write selectors for tests. Now that we have two nav menu items
with `.current-search`, some tests were failing that relied on
`$('.current-search')` returning just a single element