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`
Add process indicator to compile_test.py
fixed initializer and Wformat warnings
Merge pull request #1094 from BytesGalore/fix_print_format_warnings_test_vtimer

test:test_vtimer fixed initializer and Wformat warnings
make: print error if make was executed in the root

Fixes #1104, alternative to #1178.
Merge pull request #1183 from Kijewski/issue-1104

make: print error if make was executed in the root
Merge pull request #1079 from BytesGalore/add_NORETURNs

core: and cpu: Added NORETURN to functions that should not return
Merge pull request #1085 from Kijewski/compile_test-process-indicator

Add process indicator to compile_test.py