Migrate tox to use testr

This patch moves all unit tests to use
testr as the test runner. This means all
tests need to be subclassed from unittest
to be discovered by testr

Change-Id: I9b0e782be87ea2b5db72b56ddad1d239a83e9ee3
Closes-Bug: #1330204
Add more detail to the README

Change-Id: I7fc38226d922a894d2ae9bef1de54397bec00467
Updated from global requirements

Change-Id: Ib2515318ff672edc9dd038d2f80d9f6a9bb60428
Add pbr to dependency list

We use pbr to install stevedore, and because of the way setuptools deals
with install-time requirements we also need to include it as a runtime
dependency to ensure it is installed by pip and not easy_install.

Change-Id: I0a39bb50218a1a7cdb2d42fb474a9b8f6d6ac32a
Closes-Bug: #1384919
Bring doc build up to standard

Move the requirements definitions and documentation files to the
standard places used by other OpenStack projects so our doc publishing
jobs will work.

Change-Id: Iea630d827976fe517afacf4e373b3a125efff9c9
Update link to docs in README

Update the published link to the documentation in the README file.

Change-Id: I98006a0a47c4abbd4453ed0d05d3d00ba5dc2ea3