bumper: use DrawElements for semi-compatability with ES

also GL_QUADS isn't available with ES contexts
filterapp: port to non-glew
mixer: fix eos timestamp check
blur: port for non-glew
cube: port for non-glew
glass: port to non-glew + shader matrices
laplacian: port to non-glew
filtershader: port to non-glew
filtershader: improve error checking
mosaic: fix a couple of assertions
sobel: port for non-glew
filtercube: fix for gles2 compilation
shader: fix gles2 segfault
window: seperate object creation and context creation