WASAPI device name encoding fix, fixed skipped samples in WASAPI buffer ...

1. WASAPI device names with special characters (eg. German Umlauts) were encoded wrong when converted to std::string. This got fixed by using the same workaround as previously was used for direct sound. 
2. When using any odd ratio of the WASAPI System samplerate there were missing samples in the buffer causing bad "clicking sounds". This was caused by rounding down the buffer size in the conversion method. Using roundf before casting to int gets rid of it. The sound is still terrible because there is no interpolation, but at least it doesn't kill the speakers.