A follow-up on a previous PR GH-41. The discussion in the forum can be
viewed at http://forum.openclonk.org/topic_show.pl?pid=33086.
Run clang-tidy (without auto, pass-by-value and using checks) to fix the
header files not modified in the previous PR.
Summary of the changes:
- C++11 member initialization.
- nullptr instead of 0 for pointers.
- override for functions declared virtual in base class.
- default trivial special member functions
Not only is FMOD neither free (libre) nor free (gratis), the version we
support(ed) is also impossible to legally obtain anymore. So there's no
reason we should keep code around that (pretends to) support a library
nobody can use or test.