Remove old exec/clone system calls in favor of userspace_fexec

Removes SYS_FEXEC and SYS_CLONE, as well as CloneFlags and auxiliary vectors (as the kernel no longer knows what an auxv is). Also modifies some driver helpers to enforce the new stricter page alignment restriction.

And, Daemon has been removed. There is little reason for it to be in syscall, when it needs libc for the fork implementation!