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:  automate build test (webdriver load app.html and check output)

The difference is that the css plugin is loading dojo, while the jquery one is not loading jquery ;) Which means that:

1/ in the case of the css plugin & dojo the application developer will _not_ require the loading of dojo and so has no reason to add it to its bower.json

2/ in the case of the jquery plugin & jquery the application _will_ require the loading of jquery and so it makes sense for it to list it in the bower.json

In other words jquery plugin is just a proxy, the application developer is the one dealing with jquery and as such should be aware of that and should list it. While for css plugin & dojo that just internal "detail".