* Layer source ID is immutable; must be provided to the constructor
* Layer source layer is mutable
* Layers with GeoJSON sources do not have a source layer
While here, make Layer::copy impl-private.
* Add support for icon-text-fit
* Port unit tests for getIconQuads() from js => cpp
* Add support for padding in all 4 directions.
* Update all hashes post-merge
* First pass at port of https://github.com/mapbox/mapbox-gl-js/pull/2668
* RotationAlignmentType => AlignmentType
* Handle undefined default value for text-pitch-alignment and implement inheritance for this value from text-rotation-alignment
* Update dependencies
* Move handling fo undefined default value out of camelize functions
