This patch will show textures in the image editor with the maximum
available resolution determined by the GPU Hardware/Driver.
Currently the size is limited by the user preference texture size limit.
An image user can set the IMA_SHOW_MAX_RESOLUTION flag to request
gpu textures in the max supported resolution. When this flag isn't
set the gpu texture is limited by the user preference setting.
When the gl resolution limit is disabled the GPU texture is always
created for the max supported resolution.

