=changes from 0.9.7=
    1.  a manpage for `theme(1)`
    2. ``make install.everything'' installs sample programs, too.
    3. in `mkdio.h`, MMIOT is now a `void`, not `void*`
    4. add tests cases for style blocks and the pseudo-protocols
    5. manpages for extensions.
    6. repair `linkylinky()` so it doesn't bobble the contents of
       a [][] when it's at the end of a input stream.
    7. don't expand `*` and `_` inside tags.
    8. add `<script>` to the list of block-level html.
    9. add `<style>` support so people can add style blocks and
       programs like theme will handle them properly.
   10. the flag MKD_NO_EXT disables the pseudo-protocols.