[Voiceglue] Multiple language support

[Doug Campbell]

> I wonder if there is a way to pass a language parameter to the 
> |voiceglue_tts_gen| config file from vxml dialogs so that it would 
> generate audio in the right language.

The "xml:lang" attribute of either the <vxml> or <prompt> tags
is used for this purpose, and it can certainly be passed down.
You happen to be asking at exactly the right time as I'm just
about to make a new release, so I'll see if I can get this in.

Doug Campbell