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`
shell: print command if not found
shell: fixup test_shell expect scripts
Add process indicator to compile_test.py
vtimer: fix usage in test application
msp430: fix missing members in `struct tm`

Closes #1150.
native: initialize maybe uninitialized variable

fixes #1118
Implement core unittests
unittests: Move tests-core into subdirectoy
native: refactor one debug/errx use in irq_cpu.c
native/tramp.S: use ret instead of manual return
Merge pull request #1179 from LudwigOrtmann/native_minifix

Native minifix
Asks Git to ignore IDE-related (TI CCS) files
core/doc: complete hwtimer.h and hwtimer_arch.h
core/doc: complete queue.h
core/doc: complete io.h
Merge pull request #1041 from LudwigOrtmann/issue_951

Fix doxygen comments for hwtimer.h, queue.h and io.h
Merge pull request #1177 from LudwigOrtmann/issue-1118

native: initialize maybe uninitialized variable
Merge pull request #1154 from Kijewski/issue-1150

msp430: fix missing members in `struct tm`
Merge pull request #961 from authmillenon/core-unittests

unittests: Unittests for core module data strutures