Blender Git Loki

Fixed rendering of image textures with alpha... it gave ugly dark outlines.
Please note the following:

- pictures need to be saved as 'premul' sky render if you want to use it
in Blender as texture
- but for alpha-over in sequencer it has to be 'key alpha'...

This inconsistancy needs to be solved.. for example as option for both
texture as sequencer.