The Windows WSAStartup() and WSACleanup() functions are now called
automatically when opening and closing IrDA sockets. This causes no
problems because these functions are reference counted and can be called
multiple times.
In practice nothing changes because the Uwatec Smart backend already
called these functions for every connection.
The public header files are moved to a new subdirectory, to separate
the definition of the public interface from the actual implementation.
Using an identical directory layout as the final installation has the
advantage that the example code can be build outside the project tree
without any modifications to the #include statements.
