Initial support for DBSubnetGroup
_sign_string private_key_file can now be file-like

Distribution._sign_string is now a little bit more flexible, allowing
the private_key_file to be a file-like object (or really anything with a
.read() method).
Added support for block device mappings in autoscaling groups (re #753, #1343)
updat incorrect copyright
Add missing function parameter (re: #1357)
add integration test
cloudformation Stack DisableRollback is always True

Fix problem where DisableRollback is always true, because
bool("False") == True
Adding updated values for recurring autoscale operations
Adding updated documentation for the new variables
Merge branch 'develop' of git://github.com/boto/boto into dbsubnetgroup
Make s3 key buffer size configurable.
Merge branch 'release-2.9.4' into develop

* release-2.9.4:
  Bumping version to 2.9.4
Merge pull request #1506 from jterrace/configurable-bufsize

Make s3 key buffer size configurable.
Merge remote-tracking branch 'official/develop' into develop
Add sphinx extension for linking to github
Update release notes to use the new sphinx roles
Fix a bug always connecting to the default end point in dynamodb2's DynamoDBConnecting
Added tests for the dynamodb2 region fix.
Fix unit test

Must pass in credentials for unit tests.
Modifiy EbsOptimized param type in LauchConfig.

Since a couple of days ago, API expects a xsd1.1 boolean type for paramenter
EbsOptimized when LaunchConfiguration is created. This commit change old
True and False native python types for new lowercase string ones.