Start v5
add tiles option for remote sources
Lowercase z in min/maxzoom to match TileJSON
Use mapbox:// fontstack URL
raster-fade -> raster-fade-duration (fixes #138)
add background-opacity
Update ref description (fixes #125)
Update version
Add changelog
transition-* ⇢ *-transition

Fixes #148
Merge branch 'mb-pages' into v5

Conflicts:
	_config.mb-pages.yml
	_config.yml
	docs/index.html