Added BACKWARDS directive to Makefile for compatibility.
Completely changed the name space as per FSF's request.
Fixed a line-addressing bug introduced by previous `fix', i.e.,
space preceding a digit acts a plus (+) operator, as in `1 1' == `2',
and a plus operator by itself acts as +1, but a space by itself
should not equal a plus operator, i.e., `1 ' != `1+' == `2'.
But `s/' is still invalid, use `s//' instead.
If first regex is invalid, regex pointer is now set to NULL so that repeating
the search correctly reports "No previous pattern".
where IC is of the form [::] , [..], or [==], would incorrectly
report an error.
Fixed input mode bug: a literal ^J(i.e., ^V^J) would discard text
following it. Now, a literal ^J is treated as an ordinary ^J - i.e, it
splits a line in two.
