Fix the SDK build

Eliminate @link references to now hidden APIs. This involved mostly
reverting the docs to their 5.xml state.

One special case involved bringing
ViewGroup#FLAG_USE_CHILD_DRAWING_ORDER back into 5.xml (it was removed
from 5.xml after SDK 5 was released) 6.xml and current.xml, since it
will be needed until replacement APIs are published in 7.xml as part of
2.1
6 files changed