Documentation for exported object literals

This replaces #490 [1]. On top of @ahocevar's work, this now includes using `objectliterals.jsdoc` to replace `objectliterals.exports` completely for all generated source code, thus preserving [DRY](http://en.wikipedia.org/wiki/Don%27t_repeat_yourself).

[1] It is not possible to change the branch associated with a PR in GitHub, so I had to create a new PR.