$.formParams() should not convert arrays into single-value-attributes

Hi,

It seems that formparams omits array-types even though the input name specifically represents an array:

Given the following html:

``` html

```

The following happens currently:

``` javascript
$("#test-form").formParams()
-> { foo: "bar" }
```

But what should happen is:

``` javascript
$("#test-form").formParams()
-> { foo: ["bar"] }
```

see codepen @ http://codepen.io/tunylund/pen/IqCLF

Start at the $.formParams() entry point and trace how input names ending in [] are converted into the returned object. Reproduce the HTML example from the issue, then verify that the result preserves foo as an array containing "bar" rather than a single value.

Written by the indexing model from the issue text.