Replace __proto__ with Object.setPrototypeOf(...)

[selkhateeb]

Fixes #15. Basically, newer versions of Node > v0.11.12 started to deprecate __proto__ object member in favor of Object.setPrototypeOf(...).

To stay backward this also adds implementation for Object.setPrototypeOf.

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[selkhateeb]

Fixes #15.

[selkhateeb]

Is anybody maintaining this project any more?!