Add a mechanism for handling fatal errors (and reboots)
Implement the crash-handling/reboot mechanism for MSP430 MCUs
Implementation (incomplete) of the crash handling mechanism for ARM
Corrected 'crash.h' following recommandations of RIOT devs.
Corrected MSP 'crash.c' following recommandations of RIOT devs.
Corrected ARM 'crash.c' following recommandations of RIOT devs.
Implemented 'crash.c' for native following recommandations of Ludwig Ortmann and RIOT devs.