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
Merge branch 'develop' of git://github.com/boto/boto into dbsubnetgroup
Fix CloudFront docs to match current reality.

CloudFront's create_distribution requires origin object. To match
the spirit of the docs, update docs to reflect creating the S3Origin
object first.

This might be worse than just assuming (and documenting) that passing a
string into origin for create_distribution implies
S3Origin(dns_name='thestr'). Design decision left for later.
Added DkimTokens as a list marker.
Fix for CF resource timestamps with milliseconds
add region suppoer for elbadmin
Fixed an error in the S3 tutorial examples.
Corrected some imports in the DDBv2 tutorial.
Fixed an error in the ``get_key_pair`` docstring.
never return more than 'limit' results from a query
and make sure we simulate the behavior of the actual ws call
Merge branch 'patch-cloudformation-resource-timestamp' into develop
Added tests for more Cloudformation timestamp changes.
Fixed more Cloudformation timestamp changes.