read-regex.c: Convert escaped slash to just slash
read-regex.c: Convert escaped slash to just slash

\/ is needed in 4.0.regex because regexes there are terminated by a
bare /. However, \/ may not be defined (depending on the regex package).
Solve it by storing in the regex a bare / in that case.
(Alternatively it could be solved by a more complex code that allows
unescaped / inside a 4.0.regex expression).

linas/link-grammar,ampli/link-grammar,ampli/link-grammar,linas/link-grammar,opencog/link-grammar,ampli/link-grammar,opencog/link-grammar,opencog/link-grammar,opencog/link-grammar,ampli/link-grammar,linas/link-grammar,opencog/link-grammar,linas/link-grammar,opencog/link-grammar,linas/link-grammar,opencog/link-grammar,ampli/link-grammar,ampli/link-grammar,linas/link-grammar,linas/link-grammar,linas/link-grammar,ampli/link-grammar,ampli/link-grammar,linas/link-grammar,opencog/link-grammar,opencog/link-grammar,ampli/link-grammar