Optimize for 2 enhanced scripts

In some cases, I don't think it's worth dropping another massive chunk
of code on all pages to support some script functionality that's only
useful in one place.

For example, the scripts for the Software Page diagram are about 150k
(50k zipped). That's a bargain for what they do, but hard to justify
loading on ALL pages.

Setup ("one last thing") to be able to define ONE more script file to
load after everything else. Perfect for localized (wiki-only?
software-only?) functionality that the rest of the site doesn't need.

- replace d3 with d3.min, which seems to cause fewer conniptions on
CodeKit when minified/concat'd
- remove d3 and software diagram script from libraries
- create softwareDiagram.js extra module, loaded separately
- add framework to just define the script URL on a meta tag and have
enhanced.js load it after everything else.
- clean up some map/cruft

related to issue #21