set message type for lowpan and ipv6 notifier
notify registered threads about _all_ received IP packets

(Before notifications were only sent for IP packets that were not
forwarded.)
pointer handling in lowpan notifier was wrong
reverted 18e97f6dd5457538c7bf39c6abcf346f5a080ca5
reduce minimal timer from 100ms to 10ms
added missing timer remove on the end of the measurement
make LTC_TIMER_INTERVAL a named define
reduce LTC_TIMER_INTERVAL by the factor of 10 to be more precise
Merge pull request #310 from OlegHahm/revert_bitarithm

reverted 18e97f6dd5457538c7bf39c6abcf346f5a080ca5
Merge pull request #363 from OlegHahm/msg_fix_notifier

fixed lowpan and ipv6 notifier
Revert "pointer handling in lowpan notifier was wrong"

This reverts commit 5ccf65316455a7590f4bd18f7af54d7444b906fc.
Merge pull request #414 from OlegHahm/revert_lowpan_notifier

Revert "pointer handling in lowpan notifier was wrong"
fix: native hwtimer backend emulation

searching for the next pending timer was broken
this commit rewrites this functionality
Merge pull request #411 from mehlis/fix-native-hwtimer-backend

fix: native hwtimer backend emulation
Merge pull request #410 from mehlis/native-ltc-unregister

fix: unregister hwtimer on the end of the measurement