Get projection and axis order from GML data

To make tests pass, the winding order of the coordinates in the
test data had to be reversed to conform to common gml practice.

examples/gml.js

@@ -16,7 +16,7 @@ var raster = new ol.layer.TileLayer({
 
 var vector = new ol.layer.Vector({
   source: new ol.source.Vector({
-    parser: new ol.parser.ogc.GML_v3({axisOrientation: 'neu'}),
+    parser: new ol.parser.ogc.GML_v3(),
     url: 'data/gml/topp-states-wfs.xml'
   }),
   style: new ol.style.Style({rules: [