Make S3 region configurable (#467)
Make S3 region configurable (#467)

This makes life easier on some S3 work-alikes, which can require that
S3 operations be given region names that do _not_ correspond to those
used by AWS itself.

Fixes #465
starkandwayne/shield,starkandwayne/shield,starkandwayne/shield,starkandwayne/shield,starkandwayne/shield