add retrying http client
Fix major socket leakage
retrying http client for IAM
use my fork of httpcontrol
Merge pull request #17 from bouk/master

s3: fix major socket leakage
aws retry predicate method
only retry 5xx errors, not 4xx
move retry logic here.
all tests passing.
fast tests.
fast tests.
some todo
resilient transport constructor.
WIP
WIP
all tests pass.
comments, WIP
Merge pull request #18 from mwhooker/master

Add retrying http transport
aws: tests pass
ListResponse needs NextMarker response element