* imageHelpers: Created generic function that returns a vector of required image formats.
An upcoming commit requires access to the vector of required image formats, separatley from check_minimum_supported.
* imageHelpers: Added a new function is_image_format_required.
This function can be used to determine for any given cl_image_format, whether the implementaion is required to support it.
Conditionally test BGRA in Basic readimage3d (#623)
This change adds checks to see if testing against an embedded implementation and if so, queries whether BGRA is supported or not.
* Refactor based on PR review.
* Update passed message code.
* Changed scope of struct to be within test_readimage3d.
