MediaPlayer changes for Tungsten/Android@Home.

Squashed merge from master-tungsten of the following changes:

commit e8b156c6b224f0fe5b6a81d5f92bade36275027c
Author: Jason Simmons <jsimmons@google.com>
Date:   Fri Aug 12 10:28:48 2011 -0700

    Add a null check to handle failure of android::createPlayer

    Change-Id: Iacbbc90369a825838d4374b1f774c8880b25753b

commit 43be3231034ff8537fdd84422a7954780038671f
Author: John Grossman <johngro@google.com>
Date:   Mon Jun 27 18:59:12 2011 -0700

    Move libaah_rtp over from the vendor directory.

    Also move factor PipeEvent out into utils.

    Change-Id: Id3877c66efe22d771cf3ef4877107e431b828e37

commit 17526eb3148c9c3d4365b6d5b47e8dc13bca71b6
Author: John Grossman <johngro@google.com>
Date:   Mon Jun 27 17:06:49 2011 -0700

    Name changes for the TRTP Players s/tungsten/aah/g

    Change-Id: I55e9ad13003f6aa6a36955b54426a7efbe31ac51

commit cbf2903ab6893b6e662514e2f6d670e268a419df
Author: John Grossman <johngro@google.com>
Date:   Fri Apr 15 09:27:54 2011 -0700

    Migrate Tungsten code from the HC-Tungsten to the Master-Tungsten branch.

    Change-Id: I95372d913a0761d90168edb4016f5ece0ea74502

Change-Id: I73f3be191cd974933acddf52892e5600d253cc03
Signed-off-by: Mike J. Chen <mjchen@google.com>
Signed-off-by: John Grossman <johngro@google.com>