Rename circle-pitch-scale to circle-scale-alignment

[1ec5]

circle-pitch-scale should be renamed circle-scale-alignment.

https://github.com/mapbox/mapbox-gl-style-spec/issues/459#issuecomment-224957055 proposed {circle,icon,text}-pitch-scale properties as complements to the {circle,icon,text}-{rotation,pitch}-alignment properties. As discussed in mapbox/mapbox-gl-native#6098, the circle-pitch-scale name incorrectly implies a numeric value. It’s also inconsistent with the rest of the properties:

Property		a feature’s	according to the map or viewport’s	when the map has
circle-rotation-alignment	aligns	rotation	rotation	rotation
circle-pitch-alignment	aligns	pitch	pitch	pitch
circle-pitch-scale	aligns	scale	scale	pitch

Renaming circle-pitch-scale to circle-scale-alignment would make the property’s type more obvious and better harmonize the name with the others:

Property	does what	a feature’s	according to the map or viewport’s	when
circle-scale-alignment	aligns	scale	scale	pitch

/cc @jfirebaugh @lucaswoj

[1ec5]

An alternative to *-scale-alignment would be *-size-alignment, which would be consistent with icon-size and text-size.

[lucaswoj]

This issue was moved to mapbox/mapbox-gl-js#4165