Add methods for listing availability groups to the CloudSigma driver.
When a request is made to a CDN endpoint there is no internalURL to use, we have to fall back to the publicURL

Closes #231

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
Add a comment, use a better variable name.
Fix lint issues.
Update CHANGES.
docs: Add info on how to use ex__list_availability_groups method.
Allow user to pass ex_avoid argument to ex_create_drive and ex_clone_drive
method.
fix docs for HP Cloud

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
specify url and path for HP Cloud OpenStack examples

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
Fix lint.
docs: Update commiter guide.
Add ex_create_subscription method to CloudSigma driver. Also modify
subscription class so the amount attribute is an int.
Add auto_renew attribute to subscription class.
Include subscribed_object attribute on the Subscription class.
Allow user to create server with VLAN.
docs: Add an example of how to create a server with a vlan.
Add a test case for creating a node with VLAN.
Fix documentation build issue.
Use virtio device type.
ex_list_drives -> ex_list_user_drives.