index.js
function createAnimitter(options, fn){

    if( arguments.length === 1 && typeof options === 'function'){
        fn = options;
        options = {};
    }

    var _instance = new Animitter( options );

    if( fn ){
        _instance.on('update', fn);
    }

    return _instance;
}
function createAnimitter(options, fn){

    if( arguments.length === 1 && typeof options === 'function'){
        fn = options;
        options = {};
    }

    var _instance = new Animitter( options );

    if( fn ){
        _instance.on('update', fn);
    }

    return _instance;
}
function createAnimitter ( options , fn ) { if ( arguments . length === 1 && typeof options === 'function' ) { fn = options ; options = { } ; } var _instance = new Animitter ( options ) ; if ( fn ) { _instance . on ( 'update' , fn ) ; } return _instance ; }
create an animitter instance,
@param {Object} [options]
@param {Function} fn( deltaTime:Number, elapsedTime:Number, frameCount:Number )
@returns {Animitter}
create an animitter instance