Added native support for Dune 2000 SOUND.RS packages

They contain WAV files #3383. I read documentation about
* [SOUND.RS](http://d2kplus.com/wiki/index.php?title=SOUND.RS)
* [WAVE fact-chunk](http://www.it.hs-esslingen.de/~schmidt/vorlesungen/mm/seminar/ss00/HTML/node118.html)

and took a look at @mvi's [SoundRSEditor](https://code.google.com/p/dune2000plusone/source/browse/trunk/Dune2k1/SoundRSEditor/SoundRSEditor/Form1.cs#52) source code.

This shrinks our installer package again and it seems the explosion sound nicer without the WAV → AUD conversion I did manually months ago.