restoring CSS used in canvas label demo (whoops)
allow geometry to be offset by a given z (e.g. 'pull' a road up off the ground)
add shaders to makefile
remove some shader cruft
splitting some shaders into functions
add glslify
start moving some shader functions to glslify modules
standardize glsl var naming: u_ for uniforms, a_ for attributes
standardize glsl var naming: v_ for varyings
move shader lighting functions into glslify modules
move depth re-scale of Z coord to glslify module, and fix pop-up projection
update package.json
Merge branch 'master' into glslify

Conflicts:
	package.json
pull z layering scale factor into an external constant
directional light doesn't need vertex position
split height-based lighting boost into its own function
commented out point rendering for testing
add shader modules to makefile dependencies
move tile view & world transforms into matrix uniforms (using gl-matrix)
comment out some currently unused uniforms
split projections into perspective, isometric, and popup glsl modules