added section on building sndfile-tools for mac
added section on building sndfile-tools for mac

jniemann66/ReSampler,jniemann66/ReSampler,jniemann66/ReSampler,jniemann66/ReSampler,jniemann66/ReSampler,jniemann66/ReSampler,jniemann66/ReSampler,jniemann66/ReSampler