sort tag pages alphabetically by title on the index page

I modifed Jakefile.js to sort all the pages alphabetically by article title before generating them on index.html.

It only actually makes a difference to the tags listing (since the other articles have their order specified manually). Tags are now listed alphabetically, which makes a lot more sense.

This commit is independing on all the tag documentation pull requests (#12, #13, #15).

I didn't regenerate index.html yet though (only commited Jakefile.js) as I figure that will cause less conflicts when those other pull requests are merged.