Jquery plugin

Jquery plugin.

Since jquery's model is that every module adds functionality to the $ symbol (i.e. the variable returned by the jquery/core module), I opted to allow listing multiple modules for the plugin, ex:

 ```js
require(["requirejs-dplugins/jquery!attributes/classes,effects"], function ($){
    ...
    $(myNode).addClass("selected");
    $(myNode).animate(...);
});
```

Other things to note:

jQuery code is in jquery/src dir by default, so plugin is mapping to that directory automatically.   Seems a bit weird.

This PR also includes some other enhancements:

1. standardizing the test directories into unit/ and functional/ (like other projects)
2. upgrade to intern 2.1

TODO:

1. automate build test (webdriver load app.html and check output)
2. add reference doc
Well, if we list jquery in this project's bower.json's dependencies array, then everything just works.   Plus, jQuery is not downloaded to the browser, it's not put into a layer, etc. unless the application is using the jquery! plugin.   (This is why it's misleading to say that "it forces a dependency on jquery for anyone using this project ".)

On the other hand, if it's left up to the calling code to install jquery, that opens the door for errors such as the user downloading the production version of jquery, rather than the AMD version, or something else with a different directory structure than the jquery/src directory that we are expecting.

I don't see any practical issue here.