dist: add support for lzip compression

dist: add support for lzip compression

* NEWS: Update.
* automake.in (handle_dist): Recognize dist-lzip.
(make_paragraphs): Map LZIP to dist-lzip.
* doc/automake.texi (Dist, Options): Describe dist-lzip.
* lib/Automake/Options.pm (_process_option_list): Recognize
`dist-lzip'.
* lib/am/distdir.am (dist-lzip): New target.
(DIST_ARCHIVES) [?LZIP?]: Add `dist-lzip'.
(dist, dist-all) [?LZIP?]: Add command to create an lzip-compressed
tarball.
(distcheck): Handle lzip-compressed tarballs just like the others.
* tests/lzip.test: New test.
* tests/Makefile.am (TESTS): Add it.