chore(mixins): change animation mixing to be more flexible

The animation mixin only exept four parameters:

// Animation
@mixin animation($name, $duration, $iteration-count, $direction) {
  -webkit-animation: $name $duration $iteration-count $direction;
     -moz-animation: $name $duration $iteration-count $direction;
          animation: $name $duration $iteration-count $direction;
}

It should be more flexible to acceppt all kinds of params.
By this way you can apply any order of the parametes.

// Animation
@mixin animation($params) {
  -webkit-animation: #{$params};
     -moz-animation: #{$params};
          animation: #{$params};
}

Use case:

@import animation(m-foobar 500ms ease);

If you use a delay-time, it must follow after the duration:

@import animation(m-foobar 500ms 200ms ease);
Merge pull request #1 from macx/animation-fix

chore(mixins): change animation mixing to be more flexible