Patch from  petete.zur88, Issue 580: image.DDS_RGB_DXT1_LOAD (and similar) throw ImageException
Patch from  petete.zur88, Issue 580: image.DDS_RGB_DXT1_LOAD (and similar) throw ImageException

The problem is that the image.codecs.s3tc.PackedImageData doesn't override the
method get_texture inherited from AbstractImage.  Reusing the implementation of
_get_texture to implement get_texture fix the problem.  (There is another bug,
a function in the same module uses the unknow object 'c_ubyte', this can be
solved too using 'ctypes.c_ubyte')

arifgursel/pyglet,xshotD/pyglet,odyaka341/pyglet,xshotD/pyglet,gdkar/pyglet,shaileshgoogler/pyglet,kmonsoor/pyglet,qbektrix/pyglet,shaileshgoogler/pyglet,Alwnikrotikz/pyglet,cledio66/pyglet,Alwnikrotikz/pyglet,gdkar/pyglet,Austin503/pyglet,shaileshgoogler/pyglet,gdkar/pyglet,kmonsoor/pyglet,Austin503/pyglet,Austin503/pyglet,gdkar/pyglet,kmonsoor/pyglet,cledio66/pyglet,qbektrix/pyglet,odyaka341/pyglet,Alwnikrotikz/pyglet,xshotD/pyglet,cledio66/pyglet,qbektrix/pyglet,arifgursel/pyglet,qbektrix/pyglet,kmonsoor/pyglet,shaileshgoogler/pyglet,xshotD/pyglet,cledio66/pyglet,Alwnikrotikz/pyglet,google-code-export/pyglet,google-code-export/pyglet,google-code-export/pyglet,google-code-export/pyglet,Austin503/pyglet,arifgursel/pyglet,kmonsoor/pyglet,shaileshgoogler/pyglet,Austin503/pyglet,cledio66/pyglet,odyaka341/pyglet,google-code-export/pyglet,odyaka341/pyglet,qbektrix/pyglet,arifgursel/pyglet,gdkar/pyglet,odyaka341/pyglet,Alwnikrotikz/pyglet,arifgursel/pyglet,xshotD/pyglet