replacing umlaute and fixing address in headers Haldeneggsteig -> Universitaetsstrasse

Signed-off-by: Reto Achermann <reto.achermann@inf.ethz.ch>

Refactor and fix broken usr/testdesc
* usr/testdesc/testdesc.h had an outdated copy of include/vfs/vfstab.h in its
header file. This patch removes this duplicate header code and includes the
header.

* Remove hard-tabs from Hakefile.

* Use libDeps in the Hakefile and remove unneeded libraries.

* Add it to symbolic_targets.mk so that it gets build by the buildall tests.

* Move files from usr/testdesc to usr/tests/testdesc.

Overall, the code compiles again and also seems to work properly.