can.util: can.deparam could be a little more specific

can.deparam says it converts strings of key value pairs. Perhaps it would be helpful to at least have the term `application/x-www-form-urlencoded` in there, since that's the name of that format that I know. It might also be helpful to have a code snippet that shows how to convert an object -to- `form-urlencoded`. I would also think it's worth mentioning where it most often seems to be used: model constructors. A short example code could be:

``` js
var person = new Person(can.deparam($("form#person").serialize());
```

Find the documentation for can.deparam and review its current description and examples. Update it to identify application/x-www-form-urlencoded, explain object-to-form-urlencoded conversion, and mention model constructors with the proposed form example; done when those points are documented accurately.

Written by the indexing model from the issue text.