ImageData class to replace Bitmap class with new simpler type for core / adaptor...

ImageData class to replace Bitmap class with new simpler type for core / adaptor communication

[Issue#] N/A

[Problem]
Bitmap is a complicated abstract base class with several
interactions across core. Exposing it to the adaptor for
the simple job of moving some pixels and metadata from
disk and application memory buffers back to the core is
unnecessary complication.

[Cause]
Legacy implementation.

[Solution]
Introduce a simpler and concrete ImageData class.

Change-Id: Ia3595f496326554d73dca24215f197c97fa86b6e
Signed-off-by: Andrew Cox <andrew.cox@partner.samsung.com>