Do not zero out sched_threads needlessly

The function sched_init() zeroes out sched_threads needlessly. All
static variables can be assumed to be initialized with zero, anyways.
The C standard mandates it, and all at other places in the code it is
assumed.
Add wireshark dissector for native packets
core: msg: don't wake up sender after receive if it's REPLY_BLOCKED

solves issue #100

If the sender is reply-blocked, waking it up after its message has been
delivered is wrong. It needs to stay reply-blocked until the reply has
been delivered.
core: msg: add some debug statements
core: msg: yield after queueing of a message if REPLY_BLOCKED

When setting the running task reply_blocked, it is implicitly removed
from the runqueue. But if queueing of a msg is actually successful, the
thread exits msg_send without yielding, continuing to run even if it's
not supposed to.

Nice example of why multiple function exit points lead to weird
errors...
Use `filter` instead of `findstring`

See #672
Eliminate findstring in more places
https://github.com/Kijewski/RIOT/commit/102dc453828012985f82915ad826be069f444e61#commitcomment-5378590
fix ignore_add unused parameter warning
Fix cc110x vs cc110x_ng problems
reflect the original intent of the unused ignore_add parameter
Merge pull request #709 from LudwigOrtmann/transceiver_ignore_unused

fix ignore_add unused parameter warning
Merge pull request #665 from authmillenon/wireshark-dissector

Add wireshark dissector for native packets
Merge pull request #569 from kaspar030/dont_wake_up_reply_blocked_sender_after_receive

core: msg: don't wake up sender after receive if it's REPLY_BLOCKED
Merge pull request #662 from Kijewski/remove-sched_init

Do not zero out sched_threads needlessly
Merge pull request #701 from Kijewski/issue-672

Use `filter` instead of `findstring`
always build and initialize hwtimer

Eliminates special treatment of the hwtimer module and makes it a
mandatory part of the kernel.