Use np.frombuffer rather than np.fromstring (#1219)

Author: LourensVeen

src/amuse/ext/concurrent.py

@@ -84,8 +84,8 @@ def distribute_on_root(self):
         units_dump = pickle.dumps(units)
         attributes_dump = pickle.dumps(attribute_names)
 
-        units_dump = numpy.fromstring(units_dump,dtype='uint8')
-        attributes_dump = numpy.fromstring(attributes_dump,dtype='uint8')
+        units_dump = numpy.frombuffer(units_dump,dtype='uint8')
+        attributes_dump = numpy.frombuffer(attributes_dump,dtype='uint8')
 
         sendbuffer = numpy.zeros(4,  dtype='int64')
         sendbuffer[0] = self.shared_id