Implement changes for Rackspace compute drivers from my github pull request
(https://github.com/apache/libcloud/pull/116):

- Use auth version 2.0 by defult, remove support for version 1.1 and 1.0
- Update both drivers to work with london region even if the account doesn't
  have london endpoint in the service catalog. This is a work around for old
  accounts.
Update affected Rackspace compute tests.
Update Rackspace DNS driver to support 'region' argument.
Update Rackspace DNS driver to support 'region' argument.
Update Rackspace loadbalancer driver to use "region" argument.
Update affected deployment tests.
Update EC2 instance type map and pricing data. High Storage instances are
now  also available in Sydney and Singapore region.

Reference: http://aws.typepad.com/aws/2013/10/amazon-ec2-high-storage-hs1-instances-now-available-in-sydney-and-singapore.html
Add fixture files which I forgot to add previously.
Fix a typo.
Update tox config so Python 2.5 runs also work with the latest version of tox.