* Added aws_retry decorator function with unit tests
* Restructured the code to be used with a base class.
This base class CloudRetry can be reused by any other cloud provider.
This decorator should be used in situations, where you need to implement
a backoff algorithm and want to retry based on the status code from the
exception.
* updated documentation
* fixed tabs
* added botocore and boto3 to requirements.txt
* removed cloud.py from py24 tests, as it depends on boto3
* fix relative imports
* updated test to be 2.6 compat
* updated method name from retry to backoff
* readded lxd
* Updated default backoff from 2 seconds to 1.1s.
This will be about a total of 48 seconds in 10 tries. This is
configurable.
