Improved retry logic for throttling errors and expired credentials.

* Added additional error types to the list of throttling errors.
* Added invalid credential errors to those that need to be
  retried as expired creds

When account credentials are rotated they (the old/invalid) credentials
return a different error than when session credentials expire.  Now
catching invalid account credential errors and retrying them once
(after asking the credential provider to refresh).
Added AWS::EC2::NetworkInterface#private_ip_addresses.

Resolves #230