move the rendering code from SWGraphics.drawTextureVO(...) to SWGraphics.drawTexture(...)
remove top/bottom opacity related functionality from native
add new blend-mode as done in J2D and re-implement SWGraphics.drawTextureVO(...) - better would be to implement DRAW_IMAGE_MODE_MULTIPLY as is in OpenVG - no need for new blend mode and will work well even for non-cleared surface