Python-engineio-v3

- fixed dependency ([commit](https://github.com/miguelgrinberg/python-engineio/commit/8f8cbfd866086c3689a65bc049e0a9ce597e08c2))
- small documentation updates ([commit](https://github.com/miguelgrinberg/python-engineio/commit/d59648c663e2f54f96a824e947a86f62f45f637d))

- bug fixes on handling of timeouts in the client ([commit](https://github.com/miguelgrinberg/python-engineio/commit/de1dbbd39f8516a89525282f4d24c7d854ecb321))
- make ping loop task more responsive to cancellation ([commit](https://github.com/miguelgrinberg/python-engineio/commit/6a997b960c985b35f28b5f60f1dc8d9e99e05c08))
- correct handling of disconnect event ([commit](https://github.com/miguelgrinberg/python-engineio/commit/ccf1ddfa132a43fbe147c322608d913ede1d6c75))
- make unit tests compatible with python 3.5 ([commit](https://github.com/miguelgrinberg/python-engineio/commit/aeabccdd59f7d8939c6af47d5357e6545e9525d2))
- do not drop extra packets included in first response ([commit](https://github.com/miguelgrinberg/python-engineio/commit/0ffdb0a31b9b5be8d24d8208521fdd2121cb9a88))

- initial Engine.IO client implementation
- client examples ([commit](https://github.com/miguelgrinberg/python-engineio/commit/916bd7aa5f8df3a3caf7611133ff82cd2d0cdda7))
- pass custom headers in client connection requests ([commit](https://github.com/miguelgrinberg/python-engineio/commit/6bacd03c9cf997af09f638cbcc9e1add441edc9b))
- restructure async drivers into a subpackage ([commit](https://github.com/miguelgrinberg/python-engineio/commit/4621ff8d6ce8bd2e6dd8381ee9764887970aa056))
- documentation updates ([commit](https://github.com/miguelgrinberg/python-engineio/commit/d014ca534e20ad37c75484ae151e3cec3809c200))

- ASGI support
- support serving static files in wsgi and asgi middlewares ([commit](https://github.com/miguelgrinberg/python-engineio/commit/0c697591b44f6f849b45cec112e00331bbf537aa))
- refactor wsgi and asgi middlewares ([commit](https://github.com/miguelgrinberg/python-engineio/commit/1f7878536a62f9f5285e0a3ed8a83a9ec379d945))
- minor documentation fixes ([commit](https://github.com/miguelgrinberg/python-engineio/commit/00d713d8094233439e5bb888dd5c3b5ec363a5b1))
- reorganized documentation ([commit](https://github.com/miguelgrinberg/python-engineio/commit/84faa991890f33e8fbb5e5db884674d2dd32b1f3))

- address potential lock of the service thread ([commit](https://github.com/miguelgrinberg/python-engineio/commit/b702f6f98861e78f8c48f9aaee7b9f941de56d99))
- graceful exit for service task ([commit](https://github.com/miguelgrinberg/python-engineio/commit/2f5cd48f0f574c4cabd63f0b46dd652ff93ffc89))

- updated requirements file ([commit](https://github.com/miguelgrinberg/python-engineio/commit/2ab69b819bec6bea273b124c91cb2163b13266f3))
- more fixes towards cleaning up abruptly disconnected clients ([commit](https://github.com/miguelgrinberg/python-engineio/commit/759dc5e8a3c4301f68ffe72ac8af8422a4099dad))