Add ability to specify availability zone for subnet during creation
More fixes to AWS::Elasticache mocking

 * Implemented recommendations from @jbence review
 * Enabled tests which revealed a bug in create_cache_security_group response
Another fix from @jbence comments to simplify Excon response in authorize_cache_security_group_ingress
[Brightbox] Servers can now have their groups updated

The support was already there in fog, this code just adds documentation
comment for it
[Brightbox] Switches to new format helper

Using #data_matches_schema which correctly fails when a nullable
resource is absent.
[Brightbox] Expands on some tests

Starts checking fields that should have been altered by a request have.
[Brightbox] Adds missing images attributes
[Brightbox] Breaks schemas from test helper
Merge pull request #2124 from brightbox/brightbox_updates

Brightbox updates
[rackspace|block_storage] updated Volume#create to honor snapshot_id attribute
Attempt to fix parameter group assignment when creating AWS::Elasticache clusters.
Merge pull request #2125 from rackspace/snapshot_id

[rackspace|block_storage] updated Volume#create to honor snapshot_id attribute
Adding notifications for Rackspace Monitoring
Merge pull request #2082 from sugarb/master

Add fog Elasticache security group mocking
Merge pull request #2127 from damnitjim/master

Adding notifications for Rackspace Monitoring
AWS Data Pipeline delete endpoint does not return a JSON body string
[vcloud_director] Improve support for Tasks.

- add Organization#tasks
- add Task#cancel
- rename Task#expirity_time to expiry_time
- Task#progress is an integer
- add missing Task#start_time
- expose Task attributes introduced in 5.1 API
Merge pull request #2128 from mattgillooly/fix_aws_data_pipeline_delete_pipeline

AWS Data Pipeline delete endpoint does not return a JSON body string
add support for AWS Data Pipeline's GetPipelineDefinition endpoint

http://docs.aws.amazon.com/datapipeline/latest/APIReference/API_GetPipelineDefinition.html
add support for AWS Data Pipeline's QueryObjects endpoint

http://docs.aws.amazon.com/datapipeline/latest/APIReference/API_QueryObjects.html