Fix/clusterfinder test (#359)

- fixed test in ClusterFinderMT (use minimum one pedestal to accumulate
dummy pedestal)
- added minimum_pedestal_samples as additional constructor argument in
ClusterFinder and ClusterFinderMT
- bugfix: race conditions for empty queues in collect() - check directly
when needed

python/src/bind_ClusterFinderMT.hpp

@@ -32,10 +32,11 @@ void define_ClusterFinderMT(py::module &m, const std::string &typestr) {
 
     py::class_<ClusterFinderMT<ClusterType, uint16_t, pd_type>>(
         m, class_name.c_str())
-        .def(py::init<Shape<2>, pd_type, size_t, size_t, size_t>(),
+        .def(py::init<Shape<2>, pd_type, size_t, size_t, size_t, size_t>(),
              py::arg("image_size"), py::arg("n_sigma") = 5.0,
              py::arg("capacity") = 2048, py::arg("n_threads") = 3,
-             py::arg("queue_depth") = 16)
+             py::arg("queue_depth") = 16,
+             py::arg("min_pedestal_samples") = 1000)
         .def("push_pedestal_frame",
              [](ClusterFinderMT<ClusterType, uint16_t, pd_type> &self,
                 py::array_t<uint16_t> frame) {