Vfork now doesn't propagate color.

1. Check if CLONE_VFORK flag is set in do_fork(). If set, we set color back to original value 0.
2. Delete obselete comments.

	modified:   kernel/fork.c
Register syscall for ARM

	modified:   arch/arm/include/asm/unistd.h
	modified:   arch/arm/kernel/calls.S
Fix bug in thread coloring.

Instead of loop from input pid, we found the group leader first and loop around it to color all threads belong to the same group.

	modified:   kernel/color.c