Highlight search string match.

Change-Id: I72c0380512028674c91f287325f221a686a4821d
Improve search performance.

The normalization regex is slow (5-10ms per entry on mako), so better
pre-cache it. Also cache the icons, as the number of icons is vastly
smaller than the number of potential search results, so they'll be
reused very often.

The regex change alone brings the duration of a single filter run down
to ~20ms from ~1200ms on mako.

Change-Id: Ia0fa9c554d0d585a52c8a2b87eecbf045388c961
Settings: For the sake of search, don't split security settings.

    - There's also no good reason for having separate xml's for these.

Change-Id: I0216a2be10b801769eef7783f6c52a2b18b06aef
Settings: Disable search item in some fragments.

Change-Id: I17ed6945f34f2fe7bb18674124f8a8989145b8c1
Settings: Bump SettingsSearch db version.

Change-Id: I0ba3be71f61fcae9c2fe67064b5f890fdd0abb2c