Wxu filer aws

@ryan-roemer My implementation works under the assumption that all of the directories are the instances of a boto key object, and their key names ends with "/", like `mkdir()` creating a new key, which name ends with "/", and `rename` and `move` checking the working directory path. The side effect is that, e.g, under the directory 'foo/bar', there will be a file 'foo/bar' under directory 'foo/bar'. So `filter_objects` will remove this kind of key.

I have update `filter_objects`, and currently it displays the partial "pseudo-directories". I will update the code, like `move`, `rename_directory` to support the operations towards the partial "pseudo-directories".