Adding REDUCED_REDUNDANCY support

Simply adds $storageClass to end of putObject’s params, defaulting to
STANDARD (backwards compatible), which sets Amazon meta header
“x-amz-storage-class”

Resolves issue “REDUCED_REDUNDANCY #9”
https://github.com/psugand/CodeIgniter-S3/issues/9
Support Server-Side Encryption

I ported tpyo’s code from his “amazon-s3-php-class” repo to putObject,
where he already supported RR & SSE. I overwrote my last change for
consistency’s sake, added constants for them, swapped out ACL param
with constant (again, for consistency), and added storage class to
copyObject.

Resolves issue #4
Merge pull request #12 from daverogers/master

Adding REDUCED_REDUNDANCY support