Upgrade amqp dependency to version 1.1.0

• Upgrades underlying amqp version
  Version 1.1.0 of amqp uses newer version of amqp_client and ranch (pma/amqp@2e82976)
  Upgrading amqp should help avoid ranch conflicts that are outlined here: https://github.com/meltwater/gen_rmq/wiki/Migrations#solve-ranch-conflicts

• Ensure consumer / publisher setup is non-blocking
  #71

Upgrade amqp dependency to version 1.1.0

• Improve connection / channel cleanup on shutdown
• Verify OTP21 builds in CI

Add support for priority queues

Consumers can now declare a priority queue by setting queue_max_priority attribute.

Improve connection cleanup on different termination scenarios

• Improve connection cleanup on different termination scenarios (#33)
• Refactor consumer setup (#34)
• Downgrade ex_doc and verify doc generation in CI (#43)

Upgrade amqp dependency to version 1.0.3

• Upgrade amqp to version 1.0.3 (#22)
• Allow writing to metadata fields in publisher (#21)

Minor dependency upgrade

• Bump amqp from 0.3.0 to 0.3.1 (#19)
• Bump excoveralls from 0.8.0 to 0.9.1 (#18)
• Extend purge_queue helper to ignore non-existing queues (#17)

Make deadletter / re-connection setup configurable

• Make deadletter / re-connection setup configurable
• Publisher support headers

First release

v0.1.7

Rename project to gen_rmq (#1)