replacing umlaute and fixing address in headers Haldeneggsteig -> Universitaetsstrasse

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

systime: adding a relative timeout function

Signed-off-by: Adam Turowski <adam.turowski@inf.ethz.ch>

kernel/systime: Include more specific header

Was kernel.h, should be barrelfish_kpi/types.h.

Signed-off-by: Moritz Hoffmann <moritz.hoffmann@inf.ethz.ch>

systime: introducing system time based on time stamp counter/global timer, removing kernel_now

Signed-off-by: Adam Turowski <adam.turowski@inf.ethz.ch>