Merge branch 'avg-perf' into develop

PR #289

* avg-perf:
  Remove uneeded cast to `float` in `avg` function

Author: jamesls

jmespath/functions.py

@@ -168,7 +168,7 @@ def _func_abs(self, arg):
     @signature({'types': ['array-number']})
     def _func_avg(self, arg):
         if arg:
-            return sum(arg) / float(len(arg))
+            return sum(arg) / len(arg)
         else:
             return None