Action bar work for phones

Tweak sizing and layouts for action bar on smaller devices. The action
bar's size is now partially dependent on form factor and orientation
to conserve screen space, especially in landscape mode.

Alter the max action menu items for smaller devices. Disallow text on
action menu items with a horizontal width of less than 480dp when an
icon is available.

Remove the "Done" text on the action mode close button. (TODO: get a
properly sized 9-patch resource for this - the current one has an
intrinsic width that is too large.)

When setting an action bar icon as a resource ID, the bar will attempt
to load a mipmapped resource that is the closest available for the
target size.

Change-Id: I2498c640666ade310fdd1d3a2078bd4000b392a2