core: priority_queue: simplify inheritance
vtimer: no needless type casting

Compare https://github.com/RIOT-OS/RIOT/pull/1639#issuecomment-54713048
and following discussion.
tests: hwtimer shorten wait period

A sub-two-second period is needed for 16 bit timers.
tests/hwtimer: add self as author
Merge pull request #1643 from LudwigOrtmann/tests-hwtimer-shorten

tests: hwtimer shorten wait period
Merge pull request #1644 from Kijewski/vtimer-less-casting

vtimer: no needless type casting
Merge pull request #1639 from authmillenon/simplify_queue_inheritance

core: priority_queue: simplify inheritance
sixlowpan: ignore incoming packets if unconfigured

If there's no IPv6 address configured so far to any interface, 6lowpan
should not try to  handle incoming packets. This can easily lead to
looping packets.
sixlowpan: documented internal is_our_address()
Merge pull request #1606 from OlegHahm/sixlowpan_ignore_unconfigured

sixlowpan: ignore incoming packets if unconfigured