. correct a typo in regexp.c,
. implement a new "nc" (non-comment) feature to describe exceptions from
the comment detection; there were problems in Perl with the $# operator
that could not be solved by any other means,
. prevent blocklevel from becoming negative (due to earlier misdetected
sequences), this is probably a workaround for the problem described
in PR # bin/1785,
. update the Perl description to use the "nc" feature,
. update the man page for the "nc" and the undocumented "ab"/"ae"
features.
