[algorithm] Decode prototype content if python is older than 3.6

Fixes #71

beat/core/algorithm.py

@@ -49,6 +49,7 @@ Forward importing from :py:mod:`beat.backend.python.algorithm`
 
 import os
 import six
+import sys
 import json
 import numpy
 import pkg_resources
@@ -64,9 +65,12 @@ from beat.backend.python.algorithm import Algorithm as BackendAlgorithm
 
 
 def load_algorithm_prototype(prefix):
-    algorithm_data = json.loads(
-        pkg_resources.resource_string(__name__, "prototypes/algorithm.json")
-    )
+
+    prototype_data = pkg_resources.resource_string(__name__, "prototypes/algorithm.json")
+    if sys.version_info < (3, 6):
+        prototype_data = prototype_data.decode("utf-8")
+
+    algorithm_data = json.loads(prototype_data)
     ref_dataformats = ["integer", "integers"]
     dataformat = None