ssh: Manage stat even if BSD system.

* src/dctc/java/com/dataiku/dctc/file/SshFile.java: Add a switch for
  the option name -c/-f.
clean: Delete useless else clause.

* src/dctc/java/com/dataiku/dctc/file/S3File.java: Delete empty else
  clause.
s3: Add full hierarchy in grecursiveList.

* src/dctc/java/com/dataiku/dctc/file/S3File.java (grecursiveList):
  Add full hierchary. Upstream works for ls refactoring.
style: Refactor, sort, left-comma style.

* src/dctc/java/com/dataiku/dctc/file/BucketBasedFile.java: sort,
  left-commat style.
* src/dctc/java/com/dataiku/dctc/file/S3File.java: Refactor.
gs: Delete list method.

* src/dctc/java/com/dataiku/dctc/file/GSFile.java: Here.
file manipulation: Use already define method.

* src/dctc/java/com/dataiku/dctc/file/FileManipulation.java (isDirectSon):
  Use depth method.
Add throw exception in case of file.

* src/dctc/java/com/dataiku/dctc/file/GSFile.java (grecursiveList):
  Here.
gs: Add directory hierarchy.

* src/dctc/java/com/dataiku/dctc/file/GSFile.java (grecursiveList):
  Upstream works for ls refactoring.
Delete useless code.

* src/dctc/java/com/dataiku/dctc/file/S3File.java (constructor):
  Hierarchy added to the children list. Don't compute the directory
  paths.
gs: Compute children list.

* src/dctc/java/com/dataiku/dctc/file/GSFile.java: And pass it to the
  direct children constructor.
ls: New implementation.

This implementation is based on the recursion. Make less api call.

* src/dctc/java/com/dataiku/dctc/command/Ls.java: Here.