added notification to cmd_receive plus reactor cleanup

Added a try finally block around verify to ensure notification
deferreds are being cleaned out of the reactor

src/wormhole/cli/cmd_receive.py

@@ -75,7 +75,16 @@ class TwistedReceiver:
     @inlineCallbacks
     def _go(self, w):
         yield self._handle_code(w)
-        verifier = yield w.verify()
+        yield w.establish_key()
+        def on_slow_connection():
+            print(u"Key established, waiting for confirmation...",
+                  file=self.args.stdout)
+        notify = self._reactor.callLater(1, on_slow_connection)
+        try:
+            verifier = yield w.verify()
+        finally:
+            if not notify.called:
+                notify.cancel()
         self._show_verifier(verifier)
 
         want_offer = True

src/wormhole/cli/cmd_send.py

@@ -85,12 +85,19 @@ class Sender:
             print(u"Wormhole code is: %s" % code, file=args.stdout)
         print(u"", file=args.stdout)
 
-        key_established = yield w.establish_key()
-        print(u"Key established, waiting for confirmation...",
-              file=args.stdout)
+        yield w.establish_key()
+        def on_slow_connection():
+            print(u"Key established, waiting for confirmation...",
+                  file=args.stdout)
+        notify = self._reactor.callLater(1, on_slow_connection)
 
         # TODO: don't stall on w.verify() unless they want it
-        verifier_bytes = yield w.verify() # this may raise WrongPasswordError
+        try:
+            verifier_bytes = yield w.verify() # this may raise WrongPasswordError
+        finally:
+            if not notify.called:
+                notify.cancel()
+
         if args.verify:
             verifier = bytes_to_hexstr(verifier_bytes)
             while True:

src/wormhole/wormhole.py

@@ -289,7 +289,6 @@ class _Wormhole:
         returns a Deferred that fires when we've established the shared key.
         When successful, the Deferred fires with a simple `True`, otherwise
         it fails.
-
         """
         return self._API_establish_key()
 
@@ -582,7 +581,7 @@ class _Wormhole:
 
     def _API_establish_key(self):
         if self._error: return defer.fail(self._error)
-        if not self._key is None:
+        if self._key is not None:
             return defer.succeed(True)
         self._key_waiter = defer.Deferred()
         return self._key_waiter