Added EC2 waiters.
Replaced JMESPath gem.

Removed dependency on the `jamespath` gem in favor of the
`jmespath` gem.  The newer gem fully complies with the JMESPath
spec.
Added batch actions to Aws::EC2::Instance.

Added the following operations that can be called on collections
or batches of `Aws::EC2::Instance` objects:

* `#create_tags`
* `#monitor`
* `#unmonitor`
* `#start`
* `#stop`
* `#reboot`
* `#terminate`
Removed some un-necessary require statements for the old JMESPath gem.
Fixed constant name.
Added SQS::Message batch delete operation.

You can now receive and delete messages in batches.
This is much more efficient than deleting the messages
one at a time.

    messages = queue.receive_messages(max_number_of_messages: 5)

    # do something with messages ...

    # delete the batch of messages, makes 1 request
    messages.delete

    # delete messages one-at-a-time,  makes n-requests
    messages.each(&:delete)
Added batch delete action for Aws::EC2::Tag.

Also, Instance::Batch#create_tags no longer returns a batch of Tag
resources.  This can be added back once the resource definition supports
creating a product (n*m) resource objects from a request/response.