Updating the print dialog and its interactinos with the printing app.

1. Added support for reporting the old print attributes during layout.
   Now we keep track of the old print attributes, so the app can
   compute the delta and decide whether re-layout work is needed.

2. Fixed PrintDocumentAdapter callback interleavings. Layout callbacks
   were intermixing with write ones - a mess. Now we make an attempt
   to cancel layout and write if they respond to cancellation, otherwise
   we wait but do not interleave them.

3. Refactored the PrintJobConfigActivity for easier maintenance and
   to have a single update UI method that does the minimal amount
   of work.

Change-Id: I31ada1a0550882e6185018e6f17f923aed165d15