New shader for rainbow stickers

Also attached an example for txReflectionColor of the new sticker shader.

Now with “ksPerPixelMultiMap_AT_emissive”

Since ksEditor is unable to save alpha testing flag properly, here is a version of “ksPerPixelMultiMap_emissive” with this flag set. No other differences: both shaders would use alpha from txNormal or, optionally (with emAlphaFromDiffuse) from txDiffuse.

“Bounce back” feature for emissive shaders

That thing where surface would reflect light straight back to source, nicely described here:
https://www.youtube.com/watch?v=z5cR6EA2jGY

Use extBounceBackMask to specify channels of txEmissive having this effect.

Update, now with Stereo’s shaders

Also, emissive shaders now can work in multi-channel mode.

Initial release, first four shaders

More shaders will be available later on.