Output only the necessary vendor prefixes

- Firefox supports both animations and transforms since version 15 with the standard notation, so no need for `-moz` vendor prefixes


Also using CSS3 mixins with both transforms and animations leads to this kind of nonsense:

```css
@-webkit-keyframes pulse {
  0% {
    opacity: 1;
    -webkit-transform: scale(1);
    -moz-transform: scale(1);
    -ms-transform: scale(1);
    -o-transform: scale(1);
    transform: scale(1);
  }

  100% {
    opacity: 0;
    -webkit-transform: scale(2);
    -moz-transform: scale(2);
    -ms-transform: scale(2);
    -o-transform: scale(2);
    transform: scale(2);
  }
}
@-moz-keyframes pulse {
  0% {
    opacity: 1;
    -webkit-transform: scale(1);
    -moz-transform: scale(1);
    -ms-transform: scale(1);
    -o-transform: scale(1);
    transform: scale(1);
  }

  100% {
    opacity: 0;
    -webkit-transform: scale(2);
    -moz-transform: scale(2);
    -ms-transform: scale(2);
    -o-transform: scale(2);
    transform: scale(2);
  }
}
@keyframes pulse {
  0% {
    opacity: 1;
    -webkit-transform: scale(1);
    -moz-transform: scale(1);
    -ms-transform: scale(1);
    -o-transform: scale(1);
    transform: scale(1);
  }

  100% {
    opacity: 0;
    -webkit-transform: scale(2);
    -moz-transform: scale(2);
    -ms-transform: scale(2);
    -o-transform: scale(2);
    transform: scale(2);
  }
}
```

So that fixes it.

![ ](http://gifs.joelglovier.com/no/dikembe-mutumbo-nope.gif)