A convenient way to pass parameters to javascript functions

So when we call a helper block with parameters 
```ruby
flowplayer_for :hubble do |f|
  f.option 'foo'
  f.onLoad do
    'this.unmute();'
  end
  f.onStart do |clip|
    'alert(clip.metaData.width);'
  end
```
they will be passed to javascript
```javascript
onLoad: function() { this.unmute(); },
onStart: function(clip) { alert(clip.metaData.width); }
```