resource params doesn't treat array values properly

This issue was addressed for $http service here https://github.com/angular/angular.js/issues/1363. However, resource is currently doing its own encoding of params.

```
var R = $resource('/Path/:a');
R.get({a: 'foo', bar: ['baz1', 'baz2']});
```

results in a query like 

```
/Path/doh?bar=baz1,baz2
```

and should follow the $http encoding:

```
/Path/doh?bar=baz1&bar=baz2
```
