Initial commit
Rename list to keys

As list seems to be a reserved word in PHP, replace it by keys. It's not
a definitive choice so if you have any idea...
Fix typos in tests
Update README
Update local adaptor
Introduce ftp adapter - WIP
Add delete method to the adapter interface
Fix unit test
Fix typo in ftp adapter
Update ftp adapter - WIP
Add exists() method to file class
Add delete() method to filesystem
Add license
Fix typo in comment
Update file tests
Update ftp adapter
Fix keys() of the local adapter
Add delete() method to the file
Add adapter functional tests
Fix functional test