#120 Raspberry Pi Bluetooth output

[fred]

I tried to output espeak to a Bluetooth headset device on my Raspbean device using portaudio.
After setting up ALSA configuration this resulted in an error message and no output. After figuring out that this my be connected to an incompatible sampling rate. Espeak uses 22050Hz by default, but my configuration expects 44100Hz.
I did not succeed using ALSA rate conversion. So I tried to recompile the Espeak samples and it worked. As a side effect there is no more "slow and broken" eSpeak output for longer text sequences (compare ticket #110).
Is there any special reason why 22050Hz is used?