Issue title: Multiple select boxes (filters)
 Issue body: Hi razorjack,
thanks a lot for your work! I've got a little question. 
I'd like to use both 1) multiple data-types per Item and 2) multiple select boxes (filters).

1) multiple data-types per Item:
https://github.com/razorjack/quicksand/issues/21, particularly, edit the line: var $filteredData = $data.find('li[data-type=' + $filterType + ']'); to include " ~ " in the data type.

2) multiple select boxes (filters):
http://www.danieltulp.nl/work/quicksand-multiple.htm

The way I can get 1) doesn't work with modified Quicksand (2). Could you please help me to find out how can I combine both these functionalities?
Thanks a lot in advance!!!

 Comments: 
 Comment 0: To make it clear, I found out how to add 1) multiple data-types per Item in http://www.danieltulp.nl/work/quicksand-multiple.htm but wasn't able to add 2) multiple select boxes (filters) in https://github.com/razorjack/quicksand.

 Comment 1: Hi,

Quicksand is an animation-only plugin. It doesn't filter, sort etc. - it just animates the transition between the current state and the destination state that you provide in a parameter - so it's only about providing proper dataset for Quicksand. Quicksand doesn't need to be modified to support this feature.

Let's consider this example: http://razorjack.net/quicksand/demos/one-set-clone.html

Using firebug/webkit inspector, find Activity Monitor, Interface Builder and TextEdit, add "data-hack-tool" attribute and set its value to "true".

![Example](http://img.razorjack.net/__quicksand-20120307-004705.png)

Now let's assume that you want to pick only _apps_ that are a hack tool at the same time (so TextEdit and InterfaceBuilder). Here's how you do it:

``` javascript
var $hackApps = $("li[data-type=app][data-hack-tool=true]");
$("#applications").quicksand($hackApps);
```

And that's it! It's just a jQuery selector. You can do it in even more simple way: use classes. So you can have something like this:

``` html
<li class="util hack">nmap</li>
<li class="app hack">TextMate</li>
<li class="app hack">iTerm2</li>
<li class="app">MS Word</li>
<li class="util">System monitor</li>
```

You can select apps that are hack tools at the same time by this selector:

``` javascript
var $hackApps = $("li.app.hack");
```

So in order to use multiple select boxes, use something like this:

``` javascript
var size = $("#my-select-size").val();
var color = $("#some-select-with-color").val();

var $filteredClothes = $("li[data-size=" + size + "][data-color=" + color + "]");
$("#clothes").quicksand($filteredClothes);
```

It's just about writing proper jQuery selector to pick proper items. Quicksand will animate your picked items like a boss.

For more info about jQuery selectors, have a look here: http://api.jquery.com/category/selectors/ - it will answer all your questions.

I'll need to add another example to the docs – multiple select boxes. Looks like it would help a lot of people :).

{'source': 'GithubIssues', 'repo_name_with_owner': 'razorjack/quicksand', 'issue_id': 3493745, 'repo_stars': 1884.0}