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)

>> I think the main difference here is that css! is actually using the dojo promises in the code while jquery! is not using jquery

> I think you are really splitting hairs.

What you are doing is working and not dramatic so yes I'm somehow splitting hairs. However as I find my alternate proposal cleaner and I don't see any drawback* I still prefer it, and @clmath seems to as well. If others have an opinion I would be happy to hear it as well.

* (except for us that as you said will have to list jquery dep in several projects but I prefer to have things cleaner for our users and a little bit more complex for us. If we can really say that it will be more complex  because there are anyway tons of other projects we list at several places so it does not really make a real difference) 

> The jquery! plugin depends on jquery, and the css! plugin depends on dojo. Developers won't care about how the css! plugin depends on dojo vs. how the jquery! plugin depends on jquery.

I think that is the main point and other arguments one way or the other are just side arguments, so I will concentrate on that one.

To me the one requiring jquery in the picture is the application developer (from a requirejs-dplugins standpoint) not the jquery plugin itself. The jquery plugin is just for him a nice way of loading jquery either from AMD or from global.  

Actually in theory this plugin could be generalized to other libraries either having global or AMD modules just as jquery, so in that case would you expect all the other libraries potentially loadable by that more generic plugin to also be included in the requirejs-dplugins "just" because a plugin there can load them? I hope not? So it you scale back to jquery I think there is no reason to do it differently because even if jquery is just one lib, it can have sevearl versions for example and a consumer might want to depend on a different  version.

To some extent there should not be any difference between the jquery loader plugin and other loading mechanism (say require for example). It is here to load something but that something should not shipped as part of the mechanism to load it even though it is not fully generic.

Finally as a side note requirejs-dplugins is not just a utility module for the delite/deliteful... work. It should be thought with other consumers in mind (actually it is already used in production while delite/deliteful probably are not).