Integrating a managed version of S7Server in Sharp7

[Thieum]

At the moment, it's not possible to emulate an S7 server without the native dll, as shown in the unit tests.

It would be nice to replace the native version of the S7 server with a completely managed one, and integrate it in the Sharp7 library, as a way to replace the native dll completely, even in an S7 Server emulation scenario.