Add VoiceSpec accessor functions
Cleanup SpeechChan disposal, make it responsible for disconnecting audio file
Ugh, remove everything Etag and Byte range serve related.
- It seems that the Macintalk TTS engines do not have repeatable behavior.
There is some factor that causes the writes to the audio file to be
"aligned" on some sample boundary different from run to run. This causes
the file size to vary 16-20 bytes from run to run!