Regional Europe/Asia buckets support (tests included)

[elia]

Buckets in europe/asia require a different server, this commits solves the problem described in: http://github.com/marcel/aws-s3/issues#issue/4

introducing enpoints as in aws/s3 documentation: http://docs.amazonwebservices.com/AmazonS3/latest/dev/index.html?RequestEndpoints.html

The commit includes tests and documentation update.

Thanks, many people gets that error, Elia

[heijmerikx]

Very nice addition, would be nice if it's included!