shell: remove useless copying of input string
Add quadword math lib

GCC implicitly calls functions like __adddi3 to handle arithmetics on
long long.

Copied from http://ftp3.usa.openbsd.org/pub/OpenBSD/src/lib/libc/quad/
which is curtesy of the OpenBSD project (3 clause BSD license).
Add compile time checks to quad.h
Adapt quad lib to RIOT coding conventions
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 USEPKG variable for Makefiles

Currently pkg/USING says one should use
`EXTERNAL+=$(RIOTBASE)/pkg/<pkg_name>` to enable PKG modules.
Using this line the PKG will be compiled but not linked.

This change adds a USEPKG variable to be used like
`USEPKG += <pkg_name>`, which looks less clumsy and gets the PKG linked
in the binary.
Use include path convention for PKGs

Packages have to define a Makefile.include target in pkg/%/Makefile.
pkg/%/Makefile.include will be loaded after all other dependencies.
Apply @authmillenon's patch
Always use absolute paths with configurable paths variables
fix wiki links
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
Merge pull request #690 from LudwigOrtmann/wikilinks

fix wiki links
Merge pull request #688 from authmillenon/absolute-paths

Makefiles: Always use absolute paths with configurable paths variables
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...
added two test cases for issue #100

test_thread_msg_block_w_queue:
	demonstrates the behaviour described in issue #100
	and that it is solved by PR #569

test_thread_msg_block_wo_queue:
	demonstrates behaviour similar to the above but without
	a messge queue. This works with the current master, but
	breaks with PR #569
Merge pull request #691 from Lotterleben/test-569

added two test cases for issue #100
fix test_irq Makefile

closes #696
Merge pull request #699 from LudwigOrtmann/issue_696

fix test_irq Makefile