Ref #1096, #1097, #1099, #1100: Fix some outstanding issues with HTML JSDoc

[mtraynham]

Should resolve #1096, #1097, #1099, #1100.

For #1099, I tried splitting up the files and it seemingly fixed the paths, which also resolves #1100...

Minor caveat on #1097 (the classes). Both jsdoc2md and grunt-jsdoc (with docstrap) add the "new" keyword to these classes. Most of the documentation doesn't use it, but dc.js will work with/without the keyword...

[mtraynham]

Aww fudge, targeted for develop. Might want to pull back into master.

[gordonwoodhull]

NP, I am pretty used to cherry-picking commits rather than doing straight merges.

Working on the docs raises a weird workflow issue: develop has more (pseudo)classes than master does. Currently just the one, selectMenu, needed its own separate update on develop. I'm not sure what the best approach is here. I guess it only affects these PRs that change just about every file, so it's not worth coming up with a procedure. But it's interesting that these kinds of changes can't be made in a single PR.

[gordonwoodhull]

I merged this to master and develop. Since it doesn't affect the released code/markdown, there's no need for a tag/release, but the changes will be part of 2.0 beta 27 when that comes out.