Remove more unused code

See merge request !54

The check was already disabled by the `if (0)`.

Contrary to the documentation, `PointInElement` only returned the
values 0 (point not in element) and 1 (point in element).

This patch changes the return-type to `bool` and updates the
documentation to match the implementation.

Remove more unused code

See merge request !53

The script is no longer useful with the switch to CMake.

The same function already has a prototypes just two lines above.

The content is identical to `np/initnumerics.h`.

The macro is always defined in UG.

Remove more unused code

See merge request !52