* update highlight.js to latest release v9.13.1
* update to v9.13.1 default.css
does the current default.css include adjustments for the different languages?
* Update highlight.pack.js
* Update readme.tid
* update highlight.pack to 9.15.6
* update version number + included languages
split the latter half of highlight.pack.js into a separate file which
registers all the languages and exports hljs. this is for nodejs
compatibility and mimics the way the highlightjs module works in nodejs.