test: More test for ls, and add files for the tests.

* tests/ls.test: Here.
style: Less empty line.

* tests/run: Here.
command: Print command error on the error output.

* src/dctc/java/com/dataiku/dctc/command/abs/Command.java: Change it
  here.
ls: More test.

* tests/ls.test: Here.
test: Print the effective error output.

* tests/utils: Here. And delete the file.
test: Fix a stat test.

* tests/utils: Here.
clo: Clean parser.

* src/dctc/java/com/dataiku/dctc/clo/Parser.java: Here.
ls: Add a warning comment in ls.

* src/dctc/java/com/dataiku/dctc/command/Ls.java: Should be clarify.