Make json human readable

Fix TechEmpower/FrameworkBenchmarks#1079

toolset/benchmark/benchmarker.py

@@ -730,7 +730,7 @@ class Benchmarker:
     # Time to create parsed files
     # Aggregate JSON file
     with open(os.path.join(self.full_results_directory(), "results.json"), "w") as f:
-      f.write(json.dumps(self.results))
+      f.write(json.dumps(self.results, indent=2))
 
   ############################################################
   # End __parse_results
@@ -792,7 +792,7 @@ class Benchmarker:
     try:
       self.results["completed"][test_name] = status_message
       with open(os.path.join(self.latest_results_directory, 'results.json'), 'w') as f:
-        f.write(json.dumps(self.results))
+        f.write(json.dumps(self.results, indent=2))
     except (IOError):
       logging.error("Error writing results.json")