support for W64

```
file test.w64
test.w64: Sony Wave64 RIFF data, WAVE 64 audio, stereo 48000 Hz
```

```
du -sh test.w64
2.1G	test.w64
```

```
ssrc_hp_mac --twopass --rate 44100 --bits 16 --dither 1 --pdf 1 1 test.w64 test_44.w64
Shibatch sampling rate converter version 1.33(double precision)

unknown error 1
```