Add support for passing a query of type array to store.find.

[arjand]

Since the query is passed directly to jQuery, this array follows
the format as specified by jQuery.param.

Use Case:
I need to send multiple filter requests to the server. Since the query is passed to jQuery, jQuery.param() is responsible for serializing the array. http://api.jquery.com/jQuery.param/
The example I added to the documentation follows jQuery's serializeArray() convention.

[arjand]

Here is a a jsbin that shows these changes working with a custom built version of Ember Data:
http://jsbin.com/nonaf/1/edit

I believe I followed the Pull Request instructions in the contributing instructions, but as this is my first pull request to Ember Data please let me know what other steps I should take.

[igorT]

Thanks for the PR! I don't feel comfortable merging this by myself, but I think it looks good to me.

[arjand]

Let me know if there's any information I can provide to help make sure it is ok.
I'd like to see this merged so I don't have to keep building a custom version of Ember Data. :)

[sly7-7]

@igorT Do you feel comfortable enough now?

[wecc]

Relevant: emberjs/rfcs#27

[igorT]

We have deprecated the overloaded find, and now you should be able to pass an array to store.query