Log Message:
Update to 0.4.21:

gnome-speech 0.4.21:

* drivers/espeak/espeaksynthesisdriver.c: fix for bug #545896 - eSpeak
  segmentation fault.

gnome-speech 0.4.20:

* drivers/espeak/*: fix for bug 535493 - eSpeak driver can
  block.  The fix adds a list mechanism to handle utterances
  to be spoken and then processes them on the gidle thread.
  Also raised the maximum speech rate for eSpeak.