Improved JS Docs + added build script for JS Docs

Have been playing around with JSDoc 3 to generate Javascript documentation.
Part of the experimentation was to see if it is possible to document everything the way we need it.

To see the result, make sure you have node JS installed then run this:
`./buildjsdocs.sh`

Then open the file `build/jsdocs/index.html` in a web browser.

Or if you're lazy, I've hosted a build here: http://vincentpetry.net/ocjsdocs/

The default template looks ok but doesn't seem suitable for that many namespaces.
Still, nice to be able to browse the docs this way :smile: 

@DeepDiver1975 @icewind1991 @raghunayyar