Add public getter for isSearching

[chances]

I need to be able to know whether or not search is active when rendering my view.

Without this I can't determine if search was cancelled when the user navigated back from the search bar's LocalHistoryEntry without otherwise interacting with the search bar.

[ArcticZeroo]

Thanks, looks fine to me. Might also be worth adding a handler for when search is cancelled at some point?