Adding in S3 Loader/Storage/Result Storage

Have also added in the necessary config settings to thumbor.conf and config.py

Have taken code from some extensions I wrote to provide this functionality. You can see them at https://github.com/willtrking/thumbor_aws

These extensions are going to be used in production at upout.com very soon

Required python packages:
boto (all)
python-dateutil (storage/result_storage provides expiration functionality)

Config options:
AWS_ACCESS_KEY
AWS_SECRET_KEY

STORAGE_BUCKET

RESULT_STORAGE_BUCKET

S3_LOADER_BUCKET
S3_ALLOWED_BUCKETS