Add option "type" to DrawFeature control

The options of OpenLayers.Protocol.WFS support the attribute "featureType". If multiple types were set with an array, it's impossible to create a new feature, because as feature type the value of Array.toString is used (-> "featureType1, featureType2").
So I added to option "type" to the control OpenLayers.Control.DrawFeature. The value of this parameter will be used as feature type. 
If this parameter wasn't set and a type array is given, the first entry of the array is used now (workaround)