Merge pull request #81 from chrishajduk84/master

Fix SoftArbitraryPointSource initialization (detector name issue)

Author: flaport

fdtd/sources.py

@@ -590,7 +590,7 @@ def _register_grid(self, grid: Grid, x: Number, y: Number, z: Number):
         self.x, self.y, self.z = grid._handle_tuple((x, y, z))
 
         if self.name is not None:
-            detector_name += "_I"
+            detector_name = self.name + "_I"
         else:
             detector_name = None