fixed PyObject ref count in signal/slot connections

Author: florianlink

src/PythonQtSignalReceiver.cpp

@@ -109,6 +109,11 @@ PyObject* PythonQtSignalTarget::call(PyObject* callable, const PythonQtMethodInf
   for (int i = 1; i < count; i++) {
     const PythonQtMethodInfo::ParameterInfo& param = params.at(i);
     PyObject* arg = PythonQtConv::ConvertQtValueToPython(param, arguments[i]);
+    if (arg && (param.pointerCount == 1) && (param.name == "PyObject")) {
+      // ConvertQtValueToPython does not ref-count the PyObject, so we have to
+      // do it ourselves...
+      Py_INCREF(arg);
+    }
     if (arg) {
       // steals reference, no unref
       PyTuple_SetItem(pargs, i-1,arg);