title: AFrame extend component and override
body: <p>I am trying to extend the a-animation component but override some functionality.</p>
  
  <p>I want to add a state attribute to the parent "el", and only if the parent has that state will a mouseenter event actually trigger the animation.</p>
  
  <p>I am hoping I don't need to re-write or require a Pull request to facilitate this additional functionality as that will slow down testing and usability for me, but I would like to be able to use the main code and only "add or override" functionality.</p>