Observe changes on a nested object set after initialization across multiple observables

[ElliotNB]

We already have a test (see test 24 in test\test.js) and a solution for this issue, but the test is skipped and the solution is commented out because the solution causes IE11 performance to suffer greatly when processing very large objects.

Need to investigate whether it is possible to resolve this issue without comprising IE11 performance. We could also implement the existing solution as-is and live with the fact that IE11 will be slow for very large objects.

[Rezyan]

@ElliotNB

Since you published this issue, 4 years have passed. And since then, it has been announced the end of support and exploitation for IE11 by Microsoft. All the famous libraries don't maintain their projects for Internet Explorer anymore (I think it's a good thing, because it was difficult to be compatible with this capricious browser). So I think, in my humble opinion, that you could remove the support for IE11 (and therefore Internet Explorer as well) for Observable Slim.