Add toggleClass() to the animation abstraction

[estaylorco]

I'm submitting a feature request

• Library Version: 1.0.1

Please tell us about your environment:

• Operating System: OSX 10.x

• Node Version: 7.3.0

• NPM Version: 3.10.10

• JSPM OR Webpack AND Version JSPM 0.16.53

• Browser: all

• Language: ESNext

Current behavior: Presently, the animation abstraction offers up addClass() and removeClass(). This leads to code like this:

if (reveal) {
   this.animator.addClass(...);
else {
   this.animator.removeClass(...);
}

Not the end of the world, but a little verbose.

Expected/desired behavior: I would suggest a toggleClass() method on the abstraction. It is certainly in keeping with many of the animation libraries out there, including jQuery's, and it would allow the above to be reduced to:

this.animator.toggleClass(...);

• What is the motivation / use case for changing the behavior? Terseness, clarity, and harmony with many animation libraries' conventional approach.