add temporary 4x4 >> 3x3 matrix conversion fns/shims, pending proper 3x3 mat type
add more protocols to webgl.core, add/update context helpers, add initial extension handling/query fns
add initial impls for FBO, renderbuffer & texture handling
add :sampler2D uniform type, add RAD #define to header prefix, add new shader presets: spotlight & shadow (require more support structures)
update demo to test shadow map shader & FBO