With -o '-', stdin is read line by line and every line synthesises
immediately as its own utterance, model and speaker staying resident
across lines. Each utterance after the first opens with a fresh RIFF
header, armed at end of line and consumed lazily at the next audio,
so a client can split the stream into standalone WAV clips on the
RIFF magic. Port of the feature contributed to omnivoice.cpp in
ServeurpersoCom/omnivoice.cpp#11.
Co-authored-by: Jeffrey van Binsbergen <comgenie@comgenie.com>
Pascal
