doctor: better quick option propogation for stats

* use contextmanager for quick stats instead of editing global state
  directly
* send quick to lots of stat related functions, so they
could possibly be used without doctor, if someone wanted to
* if a stats function has a 'quick' kwarg, send the value
there as well
* add an option to sort locations in my.time.tz.via_location

my/config.py

@@ -84,6 +84,7 @@ class time:
     class tz:
         class via_location:
             fast: bool
+            sort_locations: bool
             require_accuracy: float