Drop C_MOD flag from commands that "obviously" don't need it

Drop C_MOD flag from commands that "obviously" don't need it

C_MOD prevents print functions from blocking.  The common reason for
wanting non-blocking prints are "read, print, write back" patterns.
There might be other reasons lurking in the code, and that's why
messing with C_MOD is scary.

Nevertheless, drop it from cutoff, headlines, land, lstat, motd,
neweff, payoff, qorder, sorder, and wall.  These commands have had
C_MOD "forever", even though they clearly don't modify game state.
They're all pretty simple.  Similar commands such as census, news,
ship, plane, nuke, sstat, pstat, flash never had C_MOD.