ranges like \177-\237, but accepts the character sequence from \177 to
\237. Doc fix.
(ebnf-version): New version (3.4).
(ebnf-setup): Code fix.
(ebnf-range-regexp): New fun.
(ebnf-8-bit-chars): Const fix.
(ebnf-version): New version (3.3).
(ebnf-user-arrow): Change variable customization to sexp.
(ebnf-user-arrow): Function eliminated.
(ebnf-eps-finish-and-write, ebnf-insert-ebnf-prologue): Code fix.