Improve help strings

Follow oslo.config conventions for consistency of help strings:
* Use sentence style capitalization.
* End entry with a "."
Fix capitalization of AMQP.

Change-Id: I0a6b170a2a7cfa539e06781f4495c4353d22e4d0
warn against sorting requirements

Change-Id: I64ae9191863564e278a35d42ec9cd743a233028e
Addresses-Bug: #1365061
Add square brackets for ipv6 based hosts

Closes-Bug: #1364837
Change-Id: I8f9702377cc049b74622c2db847ffac3ba946b3a
Merge "Improve help strings"
Merge "warn against sorting requirements"
Import notifier middleware from oslo-incubator

Blueprint: graduate-notifier-middleware

Change-Id: I2aa341f3e96a7344b87160609fb47e43bae5b245
Add contributing page to docs

Change-Id: I23d5220f3c3b58a92d51307637ce0424c023d80e
Merge "Add square brackets for ipv6 based hosts"
Merge "Add contributing page to docs"
Merge "Import notifier middleware from oslo-incubator"
Merge branch 'master' of https://github.com/openstack/oslo.messaging