Added more DBSnapshot attributes
Added new params to DBSnapshot unit tests
Added some missing attributes to DBInstance
documentation of launch config in Autoscaling Group was wrong

The documentation mentioned a parameter called launch_config_name, but it's really called launch_config.
typo: AIM -> IAM
Merge pull request #1882 from alexjurkiewicz/develop

typo: AIM -> IAM
add a retry when metadata fetched with a corrupt JSON format
Fixes #1868
Merge pull request #1880 from juanfont/develop

Added some missing attributes to DBInstance and DBSnapshot. Fixes #1880.
Merge pull request #1881 from luisbarrueco/develop

Fix documentation of launch config in Autoscaling Group. Fixes #1881.
PEP8 Issues
Merge pull request #1883 from henrysher/henrysher-patch-boto-utils

Add a retry when EC2 metadata is returned as corrupt JSON. Fixes #1883, #1868.
Try to use unittest2 for Python <=2.6 when testing utils - fixes an exception on older Pythons when asserting that an exception is thrown.