Migrate to cherrypy wsgi instead of eventlet

[balloob]

Description:
This migrates our WSGI server to use CherryPy instead of Eventlet. We tried a lot of approaches to get it to work but an asynchronous server just doesn't fare well with a threaded application as Home Assistant.

Things that are fixed now:

• Camera streaming completely blocked any other request from happening.
• Eventlet depended on greenlet which had a C-extension, causing installation troubles for people running it on Synology.
• No HTTP responses handled while handling a service request that came in via API

Stays compatible with the SSL work of this release.

Related issue (if applicable): fixes #2329

Example entry for configuration.yaml (if applicable):

http:

Checklist:

If the code does not interact with devices:

• Local tests with tox run successfully. Your PR cannot be merged unless tests pass
• Tests have been added to verify that the new code works.

[balloob]

CC @JshWright

[fabaff]

Just a couple of observations:

• Installation works flawless on Fedora in a venv

16-06-29 09:52:40 INFO (MainThread) [homeassistant.util.package] Attempting install of cherrypy==6.0.2

• Traceback (only first start, could be a false-positive)

16-06-29 09:52:45 INFO (Timer) [homeassistant.core] Timer:starting
Exception in thread WSGI-server:
Traceback (most recent call last):
  File "/usr/lib64/python3.4/threading.py", line 920, in _bootstrap_inner
    self.run()
  File "/usr/lib64/python3.4/threading.py", line 868, in run
    self._target(*self._args, **self._kwargs)
  File "/home/fab/Documents/repos/home-assistant/homeassistant/components/http.py", line 314, in start
    from cherrypy import wsgiserver
ImportError: No module named 'cherrypy'

• API works as expected
• SSE works as well

No issues while running for a couple of hours.

[fabaff]

And this traceback is gone too 😄

16-06-29 18:07:00 INFO (WSGI-server) [homeassistant.components.http] Traceback (most recent call last):
  File "/home/fab/.homeassistant/deps/eventlet/wsgi.py", line 506, in handle_one_response
    write(b''.join(towrite))
  File "/home/fab/.homeassistant/deps/eventlet/wsgi.py", line 453, in write
    wfile.flush()
  File "/usr/lib64/python3.4/socket.py", line 394, in write
    return self._sock.send(b)
  File "/home/fab/.homeassistant/deps/eventlet/greenio/base.py", line 379, in send
    return self._send_loop(self.fd.send, data, flags)
  File "/home/fab/.homeassistant/deps/eventlet/greenio/base.py", line 366, in _send_loop
    return send_method(data, *args)
BrokenPipeError: [Errno 32] Broken pipe

[stjohnjohnson]

So much <3