Use real Action Bar for search bar

Switched to Android standard SearchView.
Fixed a crash on GingerBread when onPrepareOptionsMenu was called too early.
Also set the app icon dynamically to avoid a jarring transition between
PageViewFragment and SearchArticlesFragment. Also fixes the ActionBar logo
for GB.

Remaining ToDos in code are marked in code with "TODO SEARCH".

Change-Id: I1b69f344da6f851ac5a1ce27ca4c7809350c5c4c