wishlist: Please support Amazon's new Standard-IA storage option

[az]

this is a forward of debian bug 799237 which lives over there:
http://bugs.debian.org/799237

the original submitter requested the following feature amendment:
---quote---
Amazon just announced a new storage option, "Standard - Infrequently
Accessed", with pricing that makes sense for storing backups. Please
consider adding a duplicity option to support it, similar to the
existing --s3-use-rrs option to use Reduced Redundancy storage.

It might make sense for the new option to support passing the name of a
storage class, rather than introducing a new boolean option, to make it
easier to add more storage classes in the future.
---quote---