Remove preventDefault() on touchstart and touchmove events (#1195)

* Remove preventDefault() on touchstart and touchmove events

Touchstart and touchmove listeners added to the document by default as passive,
so that calls to preventDefault will be ignored and will create a browser error like
"Unable to preventDefault inside passive event".

This resolves issues #1019, #1054

* Revert comment before preventDefault and put it inside touchend

Author: Archetylator

src/events.js

@@ -78,9 +78,6 @@ export default function(ctx) {
   };
 
   events.touchstart = function(event) {
-    // Prevent emulated mouse events because we will fully handle the touch here.
-    // This does not stop the touch events from propogating to mapbox though.
-    event.originalEvent.preventDefault();
     if (!ctx.options.touchEnabled) {
       return;
     }
@@ -95,7 +92,6 @@ export default function(ctx) {
   };
 
   events.touchmove = function(event) {
-    event.originalEvent.preventDefault();
     if (!ctx.options.touchEnabled) {
       return;
     }
@@ -105,6 +101,8 @@ export default function(ctx) {
   };
 
   events.touchend = function(event) {
+    // Prevent emulated mouse events because we will fully handle the touch here.
+    // This does not stop the touch events from propogating to mapbox though.
     event.originalEvent.preventDefault();
     if (!ctx.options.touchEnabled) {
       return;