Merge pull request #15 from jeroenvdgulik/master

- Allow anonymous login and added Docblox for FTP adapter
Added plugins, opens op Flysystem to thrid party plugins
Described plugins in the readme
Fixed typos
Merge pull request #16 from pborreli/typos

Fixed typos
Added tests for S3
Aparently Travis cares about classname casing
5.3 array syntax
Don't test php internals, test the package
Fixes #17: Ensure the root directory exists in the Local adapter.
Fixed #18. Zip adapter wasn't converting filenames to paths correctly
Added intial webdav support
Removed unused prefix in webdav adapter
Added Memcached caching driver
Fixed memcached example
Don't catch all of Sabre's exception, only the expected ones
Don't catch webdav listContent exceptions
Issue #8: Handle adapter exceptions better
Revert "Issue #8: Handle adapter exceptions better"

This reverts commit dc9ffe25e9ed8ddc27d66f2d7d852f987f8b3722.
Added WebDAV setup example