Many various fixes.

I merged in your recent changes and made adjustments accordingly. 

* The most important change is the use of en and em dashes instead of hyphens. En and em dashes are the proper typographical entities for ranges of values and pauses in thoughts, respectively.
* I deleted `ism.ent`. It's created by `gen.sh`, so there's no need to keep it in revision control.
* The XSLT stylesheet will add a newline between each entity declaration in `ism.ent`, to make debugging easier.
* Added HTML5 DOCTYPE.
* Fixed the Dublin Core metadata declarations.
* Added official plaintext version of CC0 1.0 copyright waiver.
* Replaced public domain releases at the top of each file with official-language copyright waivers.
* Added entry for Mohism.
* Other consistency fixes here and there.

What do you think?