working toward environment lighting
first attempt envmap
Merge branch 'master' into envmap
better envmaps
fixed image paths
Merge pull request #8 from meetar/envmap

Environment map
texture coordinate experiments
quick and dirty way to make environment map texture URL configurable
minor cleanup
fixing errant SEM angle calcs
attempt to fix errant SEM angle calc by re-centering fake perspective on screen
fix isometric projection
update build with some possible SEM fixes
added and tweaked an image
Merge branch 'master' into envmap

Conflicts:
	dist/vector-map-worker.min.js
	dist/vector-map.debug.js
	dist/vector-map.min.js
	index.html
	src/gl/gl_renderer.js
	src/gl/gl_shaders.js
	src/gl/shaders/polygon_vertex.glsl
apply lighting to envmap by default, make pre-lighting color available for custom shader transforms
Merge branch 'master' into envmap

Conflicts:
	dist/vector-map-worker.min.js
	dist/vector-map.debug.js
	dist/vector-map.min.js
	src/gl/gl_shaders.js
	src/gl/shaders/polygon_fragment.glsl
Merge branch 'master' into envmap

Conflicts:
	demos/gl_styles.yaml
	dist/vector-map-worker.min.js
	dist/vector-map.debug.js
	dist/vector-map.min.js
turn tile debug log back on
add util method for checking power-of-2 textures