man pages up to mdoc guidelines and fix some minor formatting glitches. Also fixed a number of man pages to not abuse the .Xr macro to display functions and path names and a lot of other junk.
halt before) if init is sent an interrupt signal. This is necessary for <CTL><ALT><DEL> to do the right thing if enabled.
Note: XNSrouted and routed NOT imported here, they shall be imported with usr.sbin.
