avoid adding an entry and removing it immeadiatly

[derhuerst]

This is inefficient. The unit test could maybe use ES6 Array.prototype.observe.

[brianshaler]

Why not just return at if (i>=0)?

So this..

if (i >= 0) this.data.splice(i, 1); // delete

becomes this..

if (i >= 0) return this;

(or if my pull request is merged, if (i >= 0) return;)

[derhuerst]

@brianshaler

This doesn't work. The passed value (entry) needs to be lower than the lowest value (this.data[this.data.length - 1]).