Don't reduce vocabulary in ja-dic.el by default

Don't reduce vocabulary in ja-dic.el by default

* configure.ac: Add the "--with-small-ja-dic" configure option.
* leim/Makefile.in (${leimdir}/ja-dic/ja-dic.el): Change the build
method depending on whether or not the --with-small-ja-dic option
is specified.
* lisp/international/ja-dic-cnv.el (skkdic-convert-okuri-nasi): Add
the "no-reduction" optional argument.  When it is specified, then
generate a Japanese dictionary without reduced vocabulary.
(skkdic-convert): Add the "no-reduction" optional argument.
(batch-skkdic-convert): Add the "--no-reduction" command line argument.