refactor shader creation, replace make-shader with make-shader-from-spec, add prefix header injection, specify uniform, attribs & varying as CLJ maps
add viewport helpers
add make-attribute-buffers, refactor demo to use new shader & buffer setup
bugfix native types for bool uniforms, add GLSL error parser, rename :comps attribute key into :size
update phong shader in demo
add phong shader preset as separate ns
add FBO & render buffer fns
update demo to use shader preset