Bug: can.List.splice(-1) causes JS exception inside binding framework

[isadovskiy]

Reproduced with CanJS 2.1.1.

See the example: http://jsfiddle.net/ZrWVQ/2/

In general, Array.splice supports negative index value (https://developer.mozilla.org/en-US/docs/Web/JavaScript/Reference/Global_Objects/Array/splice). But, frankly talking, I specified it by mistake in my code and got the unhanded exception. However, to my mind, such kind of faults should be handled by binding framework as well.