[rackspace|autoscale] starting on rackspace auto scale implementation
Adding models, collections and making a start on request classes
Merge branch 'auto_scale'
Initial commit for Rackspace's new Autoscale features. Most functionality is incorporated, including:
- Scaling groups
- Configuration (group configuration and launch configuration)
- Scaling policies
- Webhooks

Work remaining includes:
- Mock request classes
- Unit test coverage
Removing two superfluous files