added support for gzip / non-gzip upload to s3
change gzip config to store_as with support for gzip, json, text
move ext and mime type to config method
update extension and mime-type creation logic to use case block instead of if / else
add tests for mime-type feature
remove old gzip config after rebase from master
Merge pull request #20 from zohararad/mime-types

Support multiple storage mime-types on S3