Support for imageCubeArray, remove _EXT suffix
Support for imageCubeArray, remove _EXT suffix

This PR adds support for the imageCubeArray GLSL type (GL_IMAGE_CUBE_MAP_ARRAY).
Also, the _EXT suffix is removed from the GL_IMAGE types.
chandler14362/panda3d,grimfang/panda3d,grimfang/panda3d,tobspr/panda3d,tobspr/panda3d,tobspr/panda3d,grimfang/panda3d,tobspr/panda3d,brakhane/panda3d,chandler14362/panda3d,chandler14362/panda3d,chandler14362/panda3d,brakhane/panda3d,tobspr/panda3d,brakhane/panda3d,grimfang/panda3d,tobspr/panda3d,chandler14362/panda3d,brakhane/panda3d,chandler14362/panda3d,tobspr/panda3d,tobspr/panda3d,brakhane/panda3d,chandler14362/panda3d,chandler14362/panda3d,grimfang/panda3d,grimfang/panda3d,brakhane/panda3d,brakhane/panda3d,grimfang/panda3d,grimfang/panda3d,brakhane/panda3d,tobspr/panda3d,grimfang/panda3d,chandler14362/panda3d,tobspr/panda3d,chandler14362/panda3d,brakhane/panda3d,grimfang/panda3d