added texture for testing
added textures for testing
added edge detection pass with sobel filter
added biased separable box blur pass
fixed (?) alpha with blending mode. there's a smell here
added TODO.md
added fullscreen, teapot switch, and in-loop DOF pass
updated readme
simplifying and new passes

simplified composer.render
added EdgeDetection pass
added Dirt pass
added GuidedBoxBlur pass
added GuidedFullBoxBlur pass