Helper function for logging debug statements to the console.
 /*function _log(args) {
if (!this.options.debug) {
return;
}
var message = this._debug.commitCount + ': ';
for (var i = 0, j = arguments.length; i < j; i++) {
var arg = arguments[i];
if ((arg instanceof Object) || (arg instanceof Array)) {
message += JSON.stringify(arg);
}
else {
message += arg;
}
}
console.log(message);
} 
Sets the value for the spring, or set to `undefined` to disable the spring
function _updateSpring() {
        var springValue = this._scroll.scrollForceCount ? undefined : this._scroll.springPosition;
        if (this._scroll.springValue !== springValue) {
            this._scroll.springValue = springValue;
            if (springValue === undefined) {
                if (this._scroll.springForceId !== undefined) {
                    this._scroll.pe.detach(this._scroll.springForceId);
                    this._scroll.springForceId = undefined;
                    //_log.call(this, 'disabled spring');
                }
            }
            else {
                if (this._scroll.springForceId === undefined) {
                    this._scroll.springForceId = this._scroll.pe.attach(this._scroll.springForce, this._scroll.particle);
                }
                this._scroll.springEndState.set1D(springValue);
                this._scroll.pe.wake();
                //_log.call(this, 'setting spring to: ', springValue, ' (', this._scroll.springSource, ')');
            }
        }
    }