various: use simpler/smarter XML reading functions

Should address any XML parsing issues and allows for simpler, more maintainable
code. Should also address a crash that could occur when pasting nodes that had
inputs that weren't copied.

app/node/output.cpp

@@ -55,6 +55,8 @@ void NodeOutput::Load(QXmlStreamReader* reader, QHash<quintptr, NodeOutput*>& pa
       param_ptrs.insert(saved_ptr, this);
     }
   }
+
+  reader->skipCurrentElement();
 }
 
 void NodeOutput::Save(QXmlStreamWriter *writer) const