find: Need to manage `-type d -type f'

* src/dctc/java/com/dataiku/dctc/command/Find.java: Should print any
  directories nor files.
usage: More color.

* src/dctc/java/com/dataiku/dctc/clo/ColorPrinter.java: Follow most
  color style.
cat: Ignore -u option.

* src/dctc/java/com/dataiku/dctc/command/Cat.java: Here.
hack: How to check.

* hacking/hacking.org: Here.
test: More

* tests/cat.test, tests/find.test, tests/head.test, tests/tail.test,
  tests/mkrmdir.test: Here.
test: Extend, clean.