Refactoring/simplifying Transition code/API

Transitions used to be three phase:
- captureValues(): get all relevant property values in the
affected view targets
- setup(): set appropriate start values for affected views
prior to any transitions being played
- play(): create/play Animators for affected views

Now the second and third phases have been collapsed (and named
"play()"). This single step sets initial values for target views
and creates any Animators that should be played during the transition.
The transition mechanism stores these Animators and then starts
them at the appropriate time in the overall transition.

Issue #9507585 Transitions: Simplify Transition.play() design

Change-Id: I3fc67599b38fe49eee885dc5d32444db90b7703b