This is only a preliminary version. There is certainly some room for
improvement, but the basic functionality is already in place. That
should be sufficient for daily use, and possibles issues can always be
fixed when discovered.
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.
