S3 ACL params

• provided support of S3 storage ACL settings #6
• provided better abstraction for API classes: some logic moved to storage classes
• new methods for recursive operations to provide better compatibility across storages
• new "mkdir_mode" configuration option for Local storage
• new "aclPolicy" configuration option for S3storage
• bugfix: peview not working when connect with S3 psolom/RichFilemanager#242