Ignore query option

A bit like the `active_wrapper` one, passing a truthy value to the `ignore_query` option will result in matches even if the URL has a non-matching query string.

**Example** 
```` ruby
link_to "Madness", "/wobble", :active_on => true, :ignore_query => true
````
will match `/wobble?test=true` (or any other query string parameters).

This fixes issue #3