HRTF example has a resampling bug

[Q-Qian]

when I test ex_hrtf_spatialization function in Examples.hpp, there was no sound play out.

Reason：
the input audio's sampleRate is different from HRTF impulse sampleRate, need resample impulse array using src_simple function of libsamplerate module:

int result = src_simple(&convert, SRC_SINC_FASTEST, 1);
        if (result != 0)
        {
            std::unique_ptr<AudioBus> silentBus(new AudioBus(numberOfSourceChannels, static_cast<int>(sourceBus->length() / sampleRateRatio)));
            silentBus->setSampleRate(newSampleRate);
            return silentBus;
        }

libsamplerate project is a sub project of LabSound, after compile LabSound project, samplerate.c can't find the ENABLE_SINC_FAST_CONVERTER macro defined in CMakeLists.txt in libsamplerate/src/ :

#ifdef ENABLE_SINC_FAST_CONVERTER
	case SRC_SINC_FASTEST :
		state = sinc_state_new (converter_type, channels, &temp_error) ;
		break ;
#endif

this bug make a silence HRTF impulse, so that, the audio muted after convolved by before impulse.

[meshula]

Thanks for the report. I reproduced the problem on a machine with 48khz playback. Can you try this fix, which I pushed to top of tree? 21e4e5f