Amqpstorm

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- Set default TCP Timeout to 10s on UriConnection to match Connection [67] - Thanks josemonteiro.
- Internal RPC Timeout for Opening and Closing Connections are now set to a fixed 30s [67] - Thanks josemonteiro.

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- Fixed minor issue with the last channel id not being available.

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- Re-use closed channel ids [55] - Thanks mikemrm.
- Changed Poller Timeout to be a constant.
- Improved Connection Close performance.
- Channels is now a publicly available variable in Connections.

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- Upgraded pamqp to v2.0.0.
- Python 3 keys will now always be of type str.
- For more information see https://pamqp.readthedocs.io/en/latest/history.html
- Properly wait until the inbound queue is empty when break_on_empty is set [63] - Thanks TomGudman.
- Fixed issue with Management queue/exchange declare when the passive flag was set to True.

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- Added support for External Authentication - Thanks Bernd Höhl.
- Fixed typo in setup.py extra requirements - Thanks Bernd Höhl.
- LICENSE file now included in package - Thanks Tomáš Chvátal.

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- Added client/server negotiation to better determine the maximum supported channels and frame size [52] - Thanks gastlich.
- We now raise an exception if the maximum allowed channel count is ever reached.