added aws to register s3:// stream wrapper
moved Storage and added StorageInterface
added config for s3
added storage adapter for file and s3

adapter implementations need to specify a method to build the path to the files
using StorageInterface
configuring s3 client to register stream_wrapper if s3 storage is selected
registering StorageServiceProvider
phpdoc updates
indentation
Merge pull request #22 from dazz/storage-interface

Chose between S3 Storage and FileStorage