replace glslify with the tangram transform system
remove some unused shader code (some lighting code remains, may remove)
fix mode-specific properties in stylesheet
add Scene.rebuild() as alias for rebuildGeometry()
added color uniform to lights
changed light uniforms to 3fv
Merge pull request #71 from tangrams/lightcolor

added color uniform to lights
Merge branch 'master' into remove-glslify
Merge pull request #70 from tangrams/remove-glslify

Replace glslify with the tangram shader transform system
Merge branch 'master' into unified-build