TaskStackBuilder and Activity navigation features for framework

Promote navigation helpers from the support library to the core
platform.

The support library's meta-data element has been replaced with a
first-class parentActivityName attribute. This attribute is valid
on both activity and activity-alias elements. An activity-alias
will inherit the target activity's parentActivityName if one is
not explicitly specified.

Automatic Up navigation for Activities

Add the public method onNavigateUp() to Activity. The default
implementation will use the metadata supplied in the manifest about an
activity's hierarchical parent (parentActivityName) to do the right
thing.

If any activities in the parent chain require special Intent
arguments, the Activity subclass should override onNavigateUp() to
properly implement Up navigation for the app, supplying such arguments
as needed.

If automatic Up navigation within the same task can't find an activity
matching the supplied intent in the current task stack, it will act as
an in-app "home" and return to the root activity (presumably the app's
front page) in that task. (From this state, pressing "back" with
default behavior will return to the launcher.)

Change-Id: If163e27e59587f7af36975a09c986cb117ec3bc6