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
Introduce board blacklists and board whitelists
Split `} else {` lines per #693
replace all endless for loops by while
Merge pull request #678 from mehlis/shell-no-copy

shell: remove useless copying of input string
Merge pull request #535 from authmillenon/board-blacklists-whitelists

Introduce board blacklists and board whitelists
Merge pull request #704 from mehlis/for-while

replace all endless for loops by while
Merge pull request #572 from Kijewski/quad-math

Add quadword math library