Add support for the AMD loader

[andrewnicols]

I'd quite like to use this library in a project I work on (moodle/moodle), however JS in Moodle is loaded via AMD/requireJS.

This patch adds support for requireJS by modifying the way in which it is loaded.

I'm afraid I don't quite know where to start with adding appropriate tests for this, but existing tests continue to pass.
I have also only submitted the coffee file and not the built files. Hope this is correct.

[sorich87]

Merged with some modifications in 57ee748.

@andrewnicols how is the integration with Moodle going? anywhere I can follow it?

[andrewnicols]

Hi,

I've created a plugin for the tours which applies to Moodle 3.0, and 3.1.

We hope to get this into Moodle 3.2 core, but currently face a number of issues with accessibility which we intend to feed back here.

At some point we will be looking to move to Bootstrap 4 too.

[sorich87]

Thanks @andrewnicols. Can't wait to read your feedback about accessibility!

[sorich87]

There's a discussion about Bootstrap 4 here #554.