Implement GPX parser (read/write).

Implement a parser for GPX which supports read and write.

examples/gpx.js

@@ -0,0 +1,49 @@
+goog.require('ol.Collection');
+goog.require('ol.Map');
+goog.require('ol.RendererHint');
+goog.require('ol.View2D');
+goog.require('ol.layer.TileLayer');
+goog.require('ol.layer.Vector');
+goog.require('ol.parser.GPX');
+goog.require('ol.projection');
+goog.require('ol.source.OSM');
+goog.require('ol.source.Vector');
+
+var raster = new ol.layer.TileLayer({
+  source: new ol.source.OSM()
+});
+
+var vector = new ol.layer.Vector({
+  source: new ol.source.Vector({
+    projection: ol.projection.get('EPSG:4326')
+  })
+});
+
+var map = new ol.Map({
+  layers: new ol.Collection([raster, vector]),
+  renderer: ol.RendererHint.CANVAS,
+  target: 'map',
+  view: new ol.View2D({
+    center: [-7916461.9312699, 5226343.9091441],
+    zoom: 11
+  })
+});
+
+var gpx = new ol.parser.GPX();
+
+var url = 'data/gpx/yahoo.xml';
+var xhr = new XMLHttpRequest();
+xhr.open('GET', url, true);
+
+
+/**
+ * onload handler for the XHR request.
+ */
+xhr.onload = function() {
+  if (xhr.status == 200) {
+    // this is silly to have to tell the layer the destination projection
+    var projection = map.getView().getProjection();
+    vector.parseFeatures(xhr.responseText, gpx, projection);
+  }
+};
+xhr.send();