Add `ex_set_volume_auto_delete` to the GCE driver.

Sets the auto-delete flag for a volume attached to a node.

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
Update CHANGES.
Modify update_record method so user doesn't need to specify all the arguments.
Update Route53 driver so update_record method works correctly for records with
multiple values.
Use shorther notation.
Update CHANGES.
Re-order methods.
Add ex_create_multi_value_record method to the Route53 driver which allows
user to create a record with multiple values with a single call.
Fix links to Google Storage's documentation.

Closes #268.

Signed-off-by: Tomaz Muraus <tomaz@apache.org>
Merge branch 'trunk' of https://github.com/apache/libcloud into supply-google-creds