- introduce a talkgenerator to better share code between voice and talk generation.
- name intermediate .talkfiles after the md5sum of the text. (prevents naming problems).
- do not directly use the logger, instead emit signals.
- move talkfile and voicefile generation to base/
git-svn-id: svn://svn.rockbox.org/rockbox/trunk@21524 a1c6a512-1295-4272-9138-f99709370657