gtimer: increased resolution of the gtimer system.

This is needed to resolve a dvb tuner deadlock issued caused by my
re-jigging of the tuning setup code.
Fix #1666 - dvb: rework the adapter tuning to stop possible deadlock
Fix #1674 - remove spurious (info) log message before daemon().
support: some updates to build system
gtimer: fix live lock problem caused by wrong clock usage
dvb: demux setup code went missing!