added NORETURNs to functions that should not return
and added `UNREACHABLE();` to hint the compiler unreachable lines

added right signature for first parameter of `thread_stack_init()`
added `UNREACHABLE();` macro to `cpu/lpc1768/atom.c` and `cpu/msp430-common/cpu.c`
Exclude *.c files from make doc
Add process indicator to compile_test.py
Introduce macro to define files that should be deleted on make clean
Move .elf file to it's own target
Make directory creation in object compilation more makey
shell: renaming `isnumber` to `is_number` in sc_net_if.c

fix name collision on OS X by renaming
net: handle macro redefinitions for OS X

undefine macros and reorder header includes to get rid of system
defined macros on OS X

fixes #1165
msp430: fix missing members in `struct tm`

Closes #1150.
make: Remove `Makefile.unsupported`

This mechanism was replaced by #535. It was only used in one project.
Merge pull request #1137 from authmillenon/no_c_doc

doc: Exclude *.c files from make doc
Merge pull request #1098 from authmillenon/make-addon

make: Make make more flexible
Merge pull request #1173 from thomaseichinger/fix_rpl_udp_osx

native: net: OSX: Fix rpl_udp example
Merge pull request #1174 from Kijewski/remove-Makefile.unsupported

make: Remove `Makefile.unsupported`
native: initialize maybe uninitialized variable

fixes #1118
boards: fix license headers to LGPL

harmonises license headers in msb-430, msba2-common,
msba2 and wsn430-common

fixes #1160
Merge pull request #1176 from thomaseichinger/fix_1160

boards: fix license headers to LGPL
core: improved doxygen documentation

improved files complient to issue #950
- thread.h
- flags.h
- debug.h
- crash.h
Implement core unittests
unittests: Move tests-core into subdirectoy