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Standardize on shields.io.
Fix struct slice serialization for EC2 and Query.

Closes #22.
Serialize map request fields.

Closes #24.
Remove unused func.
Simplify True and False funcs.
Support flattened shapes.

Fixes #25.
Appease errcheck.
Reduce copies in signing.
Actually parse all shape attributes.

(Lord knows what they all do, but w/e)
More errcheck appeasement.
Don't require a session token for profile creds.
Merge pull request #28 from dpiddy/profile-creds-without-token

Don't require a session token for profile creds.
Encode time.Time fields as ISO8601 in UTC

CloudWatch requires time.Time fields ISO8601. Other APIs may require
different encodings not covered in this commit.

time.Time.IsZero() is used to check for presence of the field instead of
reflect.Value.IsValid() because the latter returns true for time.Time
zero values.

Time zone conversion to UTC is covered in the date choices in
query_test.go.

Fixes #27
Merge pull request #29 from streadway/issue27-time-fields

Encode time.Time fields as ISO8601 in UTC
Hopefully fix Route53 issues.

Fixes #30.
Add namespaces to REST-XML request entities.
Merge pull request #31 from stripe/possible-route53-fix

Hopefully fix Route53 issues.
Possible fix for REST-XML lists.

Related to #30.