Will cause any line that contains the string specified to not be checked for
substitutes and gags. The ^ char starting a string will tell the client to
only antisubstitute lines that START with the string specified.
examples:
#antisub {^You}
any line starting with 'You' will not be checked for subs.
#antisub {^You%0hit.}
lines that start with 'You', and also contain 'hit.' will not be subbed.
#antisub {annihilate}
any line that contains the word 'annihilate' will not be subbed.