hunter: sniffer: never take timestamp from PacketTimeStamp.

It seems that PacketTimeStamp uses some timebase other than the system
timestamp of the hunter mote.
http://www.tinyos.net/tinyos-2.x/doc/html/tep132.html should tell more,
for the moment it is disabled, we don't need exact timestamps  anyway.
We use system time (of the hunter mote) instead.
hunter:  java: remove unused counter
compass: improve test code to write out yaw, roll and pitch
hunter: mote + java: change default radio channel to 16