###stringlist-regexp###
converts a list of strings to a nested regexp.
function( strings, [ matchStart: true , matchEnd: true ])
example:
`stringListRegExp(['foo','bar','baz']); //yields (^foo$|b(ar$|az$))
stringListRegExp(['foo','foobar','bar','baz'], true, false); //yields (^(foo(bar)?|b(ar|az)))