Fixed Filesystem::listKeys
Escape forward slashes
Added phpseclib sftp adapter
Set S3 permissions during file write

I've added this since with GaufretteBundle you can't use AclAwareAmazonS3 and this would be a nice way to set file permissions on write.
Added acl into class options and acl getter/setter
Merge pull request #181 from nmpolo/regexfix

Escape forward slashes
Merge branch 'patch-1' of https://github.com/alex88/Gaufrette into alex88-patch-1
Add spec for acl handling in amazon adapter. Renaming of spec methods.
Merge pull request #174 from hason/phpseclib

Added phpseclib sftp adapter
Merge pull request #170 from hason/listKeys

Fixed Filesystem::listKeys