Fixed TestWatcherInitialization.test_copy_path test

More than one Queue.get call is needed to get full
output from a watcher in an environment with rich sys.path.
Fixed Arbiter.reload_from_config (httpd and statsd stopped)

circushttpd and circusd-stats watchers were stopped for no reason.
reload_from_config does not allow [arbiter] changes, so sockets
and watchers created on [arbiter]'s behalf should be ignored when
looking for changes.
Use loads and dumps functions from zmq.utils.jsonapi
Change deprecated assertEquals to assertEqual everywhere
Wrap dict iterators in list for Py3 support
Use zmq.utils.strtypes b and u instead of s2b and b2s from py3compat
Switch to json loads/dumps in zmq
Convert to bytes or str where necessary for Py3
Move toboolean from DefaultConfigParser to StringConfigParser and use a different property for Py2 or Py3 for boolean states
Put keys in a list for Py3
Sort by key in env_to_str so tests are deterministic
Use different sort method for Py3
Fix typo in __next__ for Py3
Fix raise_with_tb to work on Py2 or Py3
Simplify iter_watchers so that it returns consistent results on Py2 and Py3
More type conversion for Py3
Remove unnecessary type conversion since zmq JSON dumps handled it for us
For cmd string to lower since 'python' == 'Python' on Mac OS X
Use SIGKILL instead of SIGSEGV in test_unexisting so we don't get 'app crashed' dialogs on OS X

Also suppress the exception reporting for tornado.application when we crash the app
Convert data to string for Py3