migration to 3.1
Fix layer.filter for  conversion
notworking: working on converting size fns to halo-width fns where size spec by constants
Converts text-halo-width to pixels
travis-ify JS
Captures exponential and linear functions in text-halo migrations, constants in text-halo-width
travis-ify fn migration
rename v3.1 to v4
Migrate glyphs to top level

https://github.com/mapbox/mapbox-gl-style-spec/pull/77
Validate v4
Git URL for spec
Promote render `type` property to parent layer
Merge branch 'master' of github.com:mapbox/mapbox-gl-style-lint into v3.1
Merge pull request #17 from mapbox/layer-type

Promote render `type` property to parent layer
delete render property if empty after type promotion
Really delete render property if empty after type promotion
these are not separate properties
v4 migration icon type issues
Fix validation for arrays of functions
text-path: curve > symbol-placement: line, rm symbol-rotation-alignment