When we replaced the action bar docs with the new app bar docs,
we chose not to document the deprecated "overlaying the action bar"
functionality. Removing a separate training section that relies on
the now-removed material.
bug: 26502436
Change-Id: I0fe3715a39d5591be6eecbacbd7f68134ecc9f96
Removed the now-obsolete ActionBar API guide; it's been
superseded by the AppBar training class
(http://developer.android.com/training/appbar/ )
Changed the most important ActionBar links and references to point to
the AppBar docs (or some other appropriate page).
A separate CL will set up redirects from the ActionBar API guide.
See first comment for doc stage location.
bug: 25194804
Change-Id: I0859ea1712971fcf2f6cf131b2a5221b5bf3ea44
