MP support

[OlliV]

• [ ] Ensure proc MP safety
• [ ] Current proc/thread global variables are not valid for MP
  • Global variables for current task can't be used on MP system:
  • [ ] extern volatile pid_t current_process_id;
  • [ ] extern volatile proc_info_t * curproc;
  • [ ] extern volatile threadInfo_t * current_thread;
  • These should be possibly replaced with arrays which specify current value for each core.
• [ ] MP scheduling support is only partially implemented and lacks testing