master: store run_time and start_time as doubles

RELEASE_NOTES.rst

@@ -51,6 +51,8 @@ Release notes
 * The PDQ(2/3) driver has been removed and is now being maintained out-of tree
   at https://github.com/m-labs/pdq. All SPI/USB driver layers, Mediator,
   CompoundPDQ and examples/documentation has been moved.
+* The results keys start_time and run_time are now stored as doubles, rather
+  than ints.
 
 
 2.4

artiq/master/worker_impl.py

@@ -287,8 +287,8 @@ def main():
                     dataset_mgr.write_hdf5(f)
                     f["artiq_version"] = artiq_version
                     f["rid"] = rid
-                    f["start_time"] = int(start_time)
-                    f["run_time"] = int(run_time)
+                    f["start_time"] = start_time
+                    f["run_time"] = run_time
                     f["expid"] = pyon.encode(expid)
                 put_object({"action": "completed"})
             elif action == "examine":