Fixed EMR's describe_cluster_command
Merge pull request #2034 from pasc/describe_cluster_bugfix

Fixed EMR's describe_cluster_command. Fixes #2034.
Added & updated some EMR unit tests
Add support for Route53 2013-04-01
Merge pull request #2080 from danielgtaylor/route53-update

Route53 API update to 2013-04-01. Fixes #2080.
Altered ``get_bucket`` to use ``HEAD``.

This is mostly backward-compatible (& less expensive). However, if you were parsing exception messages from this method, you should refer to the documentation on how to change your code.
Updated the wording to stress that thousands of
keys weren't being fetched before.
Merge branch 's3-get-bucket-fix' into develop
Fixes #2082, #2078.
Fixed a test failure in Route53.