feat: support ioctl() syscall for direct control to devices

feat: add ascii control code support to lunaix tty driver
feat: expose the syscall interface of getpgid() and setpgid()
fix: race condition when issuing SIGINT to process group.
fix: dead lock when a process get terminated while it is holding the inode lock
fix: double freeing the v_file object when terminating a process which it's fd is dup()ed from it's parent process.
todo: taskfs is still problematic..
chore: fixes and refactor.