Implement text rendering along paths

This commit also changes the TextReplay.drawText() signature, and moves
geometry calculation into drawText(). This improves performance where no
text needs to be rendered (TextStyle.getText() == ''), which is used often
in applications.

package/package.json

@@ -8,8 +8,7 @@
   "dependencies": {
     "pbf": "3.0.5",
     "pixelworks": "1.1.0",
-    "rbush": "2.0.1",
-    "@mapbox/vector-tile": "1.3.0"
+    "rbush": "2.0.1"
   },
   "browserify": {
     "transform": [