Souper Secret Settings

a few changes ive slowly done over the past few months, no update to a modern version yet

• added new shader soup:pallete_dither, which is quite laggy, but dithers with a set colour pallete (badly implements a technique described by Azzy)
• added new shader soup:emboss
• added new modifier soup:cross, which returns the cross product of the base and the shader stack
• changed some of the parameters of soup:hyperspace (this will mess with any saved layers if they modified the parameters of soup:hyperspace)
• soup:multiply modifier can now xor
• soup:fisheye now works with luminance alpha