Pyads

* AdsLib: allow UNIX flavors to build more easily

* add support for ctypes.Structure in notification callback decorators

* remove race-condition related to the notification decorator, thanks to Luka
Belingar for the bugfix

* bugfix: notifications on Windows didn't work

* bugfix: do not call add_route or delete_rout on Windows platform in Connection class
* increased coverage

With version **3.0.1** only the extended ADS functions will be used. This allows to use
the same library functions for Linux and Windows. As a result the *pyads.py* module has
been removed from the package. Certain older versions of TcAdsDll don't support the 'Ex'
set of functions. If you experience trouble please update your TwinCAT version.

The new version also comes with completely covered PEP484 compliant type-annotations. So
you can conveniently apply static type-checking with mypy or others.