Added fitting with lmfit (#128)

- added stand alone fitting using:
https://jugit.fz-juelich.de/mlz/lmfit.git
- fit_gaus, fit_pol1 with and without errors
- multi threaded fitting

---------

Co-authored-by: JulianHeymes <julian.heymes@psi.ch>

python/src/module.cpp

@@ -8,6 +8,7 @@
 #include "pedestal.hpp"
 #include "cluster.hpp"
 #include "cluster_file.hpp"
+#include "fit.hpp"
 
 //Pybind stuff
 #include <pybind11/pybind11.h>
@@ -29,5 +30,6 @@ PYBIND11_MODULE(_aare, m) {
     define_cluster_file_io_bindings(m);
     define_cluster_collector_bindings(m);
     define_cluster_file_sink_bindings(m);
+    define_fit_bindings(m);
 
 }