[GLJS-586] Added/fixed support for GLJSv3 (#520)

* Added support for GLJSv3
* Use latest firefox for testing

Author: underoot

.travis.yml

@@ -2,6 +2,7 @@ language: node_js
 node_js:
   - '12'
 addons:
+  firefox: latest
   apt:
     update: true
     packages:

debug/index.js

@@ -27,7 +27,8 @@ mapDiv.style.bottom = 0;
 
 var map = new mapboxgl.Map({
   container: mapDiv,
-  style: 'mapbox://styles/mapbox/streets-v9',
+  // update to Standard after fix of GLJS-624
+  style: 'mapbox://styles/mapbox/streets-v12',
   center: [-79.4512, 43.6568],
   zoom: 13
 });