Adding reconnecting async ssl example

- async_reconnecting_ssl_client.py will automatically close and
reconnect to a server when it becomes available (rather than hanging or
dying when the server disappears)

examples/thread.capnp

@@ -8,4 +8,5 @@ interface Example {
 
   longRunning @0 () -> (value: Bool);
   subscribeStatus @1 (subscriber: StatusSubscriber);
+  alive @2 () -> (value: Bool);
 }