updated callback in README
setting up basic example
generalizing code
abstacting api
abstracting layering
new example, indexing for multiple textures must start at 1
index textures starting at 0 again. cache some variables
multiple layers example working
switch image layer and program easily.  clean up code
documentation
fixed viz for non-square images
removed stat function
clean up examples, tweaks to api
canvas api
canvas color composite implemented