Implement new Cloudsearch API 2013-01-01 as cloudsearch2 module
Pass partial= param into query layer
Handle case where self.domain isn't defined and we have to default to some API version number. Use new 2013-01-01 in this case.
CloudSearch2 updates

Changes the following:
* Generated layer1.py from service model
* Layer1 -> CloudSearchConnection
* Layer1 now uses JSON instead of XML responses
* Updated layer2 objects to use JSON and generated layer1
* Updated doc service to remove attributes which are no longer valid
* Updated search service to remove attributes which are no longer valid and
  modify existing attributes which have changed
* Updated unit tests and integration tests for all of the above
Documentation Updates

* Fix class/module names in the docs files for cloudsearch and cloudsearch2
* Remove param doc comments that no longer exist
* Normalize the parameter help text for domain_name
Fix copyright year
Use isinstance instead of type()
Remove unused wait_for_state function
Merge branch 'danielgtaylor-cs2' into develop

* danielgtaylor-cs2:
  Remove unused wait_for_state function
  Use isinstance instead of type()
  Fix copyright year
  Documentation Updates
  CloudSearch2 updates
  Handle case where self.domain isn't defined and we have to default to some API version number. Use new 2013-01-01 in this case.
  Pass partial= param into query layer
  Implement new Cloudsearch API 2013-01-01 as cloudsearch2 module
Add support for Route 53 failover record sets and clean up the associated test.
Update DynamoDB to support query filters
Fix dict syntax in example
Merge pull request #2242 from danielgtaylor/ddb-queryfilter

Update DynamoDB to support query filters. Fixes #2242.
Include resource records commit unit test for Route 53
Merge pull request #2236 from leezen/develop

Add support for Route 53 failover record sets and clean up the associated test. Fixes #2236.
Add support for SQS message attributes
Merge pull request #2257 from danielgtaylor/sqs-message-attributes

Add support for SQS message attributes. Fixes #2257.
Add Cloudsearch2 reference docs to index
Added release notes for 2.28.0
Version bump to 2.28.0