cpu/stm32f3: c++: initial support for c++, added _kill (weak) and weak attribute for _kill_r
boards/stm32f3discovery: provided c++ feature (cpp)
Merge pull request #1989 from BytesGalore/EasyCPPMixing_stm32f3discovery_support_fix

cpu/stm32f3 C++ stm32f3discovery support fix
native: add daemonize argv filter

When daemonizing, only the first instance should do so.
Merge pull request #2020 from LudwigOrtmann/native_daemonize_filter

native: add daemonize argv filter
native: add fileno wrapper
native: disable interrupts for reboot
native: add "fildes" module (WIP)