Object Versioning: some clean-up..
Object Versioning: get-trap: return prototype property as is
Object Versioning: transform instanceof to Object.instanceOf

there's no trap for the instanceOf operator, yet. instead it always
works directly on the proxy's original target (dummyTarget for our
fully virtual object-proxies), which might by now have a changed
prototype-chain.

further, a function's prototype property is proxied, whereas all
objects in the __proto__-chain of an object aren't proxied.. that is,
even resolving the __objectID to the current version of an object would
not be an instanceof its constructor..
Object Versioning: source transformation for wrapping Object

can't wrap Object globally, as it's also used in reflect.js (and OV
code) and can't be patched in Chrome anyway

so rewrite: Object -> lively.proxyFor(Object)
Object Versioning: Object -> lively.proxyFor(Object)

as Object !== lively.proxyFor(Object), but this check happens when,
for example, code checks whether the prototype chain of an object ends
in Object..