Treating geometry as just another attribute

The first set geometry is considered the default.  As an added bonus, we're back to a single argument constructor.  Later, we could allow a schema to be set.  This would be done before setting values (calling constructor with no args).

test/spec/ol/style/line.test.js

@@ -30,7 +30,7 @@ describe('ol.style.Line', function() {
         strokeWidth: ol.Expression('widthAttr')
       });
 
-      var feature = new ol.Feature(undefined, {
+      var feature = new ol.Feature({
         value: 42,
         widthAttr: 1.5
       });