utils: add -DWITH_DOC -DWITH_TEST in Preferences

We add the two options WITH_DOC and WITH_TEST in Preferences. Theses
options are used when the users selects the configure package mode.
vle: fix executable status return

The status of the executable is badly in the package mode, if now no vpz
provided. For example, the following commands failed (even if rclean
success):

	$ vle-1.1 -P vle.output rclean