Bring repository up to speed

    * Adds the "build" folder to be ignored by git
    * Adds CONTRIBUTING.rst file contribution instructions.
    * Adds HACKING.rst for hacking guidelines
    * Renames README > README.rst to be more inline with other client repos.
    * Moves *requirements.txt into root to be inline with other repos.
    * Adds LICENSE with Apache license contents
    * Changes project to use PBR for versioning etc instead of hardcoded
      versioning - other change is being made in order to tag the client
      repository to utilize TAGS / git SHA1 for versioning instead when doing
      sdist etc..

Change-Id: I707fb628cd292be807e6e0fd7ad0062635051953