show newest toast instantly even with limit reached

**Do you want to request a *feature* or report a *bug*?**
feature

**What is the current behavior?**
With a set limit, when that limit is reached, newer toasts are added to a queue and displayed as soon as a new slot is free. Thats fine, but I want to suggest a new behavior to be along with this.

**What is the expected behavior?**
Instead of adding the new toast to a queue, close the oldest toast and instantly add the new one to the container. To control this behavior, perhaps there could be a boolean property "showNewestInstantly", with false as default value to keep the current behavior as the default.

Thanks