Adding a timer test.

Fix initialization bug in handler that was causing flags
to have indeterminate value.
Working on acceptor/connector.

- Fix the connector.
- Implement syncrhonous connection (not tested).
- Fixing dtor ordering bug with reactor/handlers where
the reactor would call destroyed objects.
Changing shutdown semantics.

- When reactor's run() stops, outstanding handlers are
  removed.
- The shutdown() function is renamed to remove_handlers().
Implement reactor time slicing.

- Add a new overload of run() that takes a specified duration.
- Rewrite previous run() in terms of new overload.
Stubbing out pretty printing facilities.