module.paths is undefined inside sandbox

Some modules use [undocumented](https://nodejs.org/api/modules.html#modules_the_module_object) property `module.paths`, but it seems that `Module` instance, that is used by `sandboxed-module`, lacks of that property.

I think the property (and maybe some others) could be simply [monkeypatched](https://github.com/felixge/node-sandboxed-module/blob/master/lib/sandboxed_module.js#L70) to make sandbox look closer to the native environment.