Hardware Composer Stress Test Enhancements

Enhancements include:
  + Change default delay after each set operation
    from 0.1 to 0.0 seconds.  This significantly
    increases the default rate at which operations
    are performed.

  + Make sourceCrop to displayFrame scale
    factor of 1.0 a frequent occurance.

  + Enable use of RGB888 and YV12 graphic formats.

  + Add initCheck() call after creation of a
    GraphicBuffer, to confirm it was created
    without any errors.

Change-Id: I1606dff3924a23bdd5cb27ba302bebb4f200d768