Improve menu button behaviour, make playlists and search more visible.

The actionbar compatibility code is moving excess actionbar items to the
action overflow.  Currently this is a popup menu, which is activated by
an overflow icon.

In the native ActionBar, "the overflow icon only appears on phones that
have no menu hardware keys. Phones with menu keys display the action
overflow when the user presses the key."

Since all pre-honeycomb devices have menu keys, and we only use the
compatibility code on pre-honeycomb devices, it is safe to leave excess
actionbar items in the options menu.

This simplifies the code somewhat, while providing additional space on
the action bar.

The extra space is used to display an additional icon on the action bar.
Additionally the Ifroom option is now supported. The calculation of how
many icons to display is done as described in
http://developer.android.com/design/patterns/actionbar.html, except that
the restriction of "Action buttons in the main action bar may not occupy
more than 50% of the bar's width" isn't checked. The withText option is
still not supported.

Merges commit '77c6959d9668f757e005c0c2435d9567d106d9e4' into actionbar
Correct some string resource names that were mis-merged.