Add prompt to choose Bootstrap JS framework

[tomwayson]

In my local branch I've added a prompt so the user can choose whether they want to use jQuery or pure Dojo for the Bootstrap JavaScript, much like the new Bootstrap Map demo page. This is what the prompt looks like:

If the user selects Dojo, jQuery and the Twitter Bootstrap are not added to the page and Dojo-Bootstrap is loaded via AMD instead. Calls to $() are replaced w/ query().

If the user selects jQuery the output is the same as existing generator.

You can see a live example of the Dojo output here: http://tomwayson.github.io/yo-dojo-bootmap/

If you're interested I can make a PR w/ this, otherwise, I might fork and make a generator-dojo-bootmap. This is based on the commits in PR #1, so that would have to be merged first if you want me to PR.

Here's the diff

Thanks!