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
Adjust part size as needed in create_archive_from_file

Fixes #1478, original patch suggested by @dminkovsky.
If we have a large enough file such that the default part size
is not sufficient to stay within the maximum number of parts
allowed by glacier, we automatically adjust the part size
to the minimum required.  We were previously calculating this
value but not actually doing anything with it.
Add release note item for bug fix
Merge branch 'glacier-partsize-fix' into develop

Closes #1478

* glacier-partsize-fix:
  Add release note item for bug fix
  Adjust part size as needed in create_archive_from_file
Merge pull request #1503 from reinhillmann/develop

Fixed regex that failed on S3 buckets with uppercase letters.
A few PEP8 fixes and added some missing files to the EC2 ref docs index.
Merge branch 'develop' of github.com:boto/boto into develop
Make s3 key buffer size configurable.
Fixing cloudformation time stamps when API returns milliseconds
Added tests for the cloudformation millisecond bug.
Merge branch 'cloudformation-millis' into develop