Object Versioning: removed the Lively classes benchmark..

the simple benchmark, intended to test whether our proxies work correctly with
Lively's class system' and Morphic implementation, wasn't actually isolated enough to test those features _without_ running the whole Lively Kernel with
proxies..
Object Versioning: added other v8 / Octance benchmarks
Object Versioning: added getOwnPropertyDescriptor-trap
Object Versioning: new versions for all kinds of write access

Object.defineProperty, .preventExtension, .seal, .freeze and
delete Object.property is also write access that should not manipulate
versions of objects commited with previous versions of the system
Object Versioning: renaming: targetObject -> currentVersion