Returns an array representation of this up.Params instance.
The returned value is a JavaScript array with elements that are objects with
{ key } and { value } properties.
Example
var params = new up.Params('foo=bar&baz=bam')
var array = params.toArray()
// array is now: [
// { name: 'foo', value: 'bar' },
// { name: 'baz', value: 'bam' }
// ]
