This works around the incorrect shadow on the edge of the Signed Distance Field, but it does not get rid of it completely. Due to linear sampling it will still show at some point so a different solution has to be found in the future.
Colored shadows previously had an effect on the image color, but this is incorrect if the image is fully opaque. This fixes it by using premultiplied alpha mixing instead.
Sources were rendering with a black border around them if they had a soft fade, which is due to how the shadow calculated the image sample. With the new shader code this is now fixed and the source looks like it should be. Additionally this removes the bug where enabling any shadow would cause only the texels to draw that were above the threshold.
Additionally this adds support for inverse gradients (min > max) and negative gradients for outer shadows instead of only positive gradients. This technically allows for cleaner shadows.
Adds Inner/Outer Shadows for dynamic sources based on signed distance field generation. This is fast, but does add a bit of latency when it comes to updates - which means that moving objects will leave a trail before the generator has a chance to update.
Fixes#3
