[Voiceglue] Detect DTMF start

[Doug Campbell]

> When I press star I get nomatch.

The voiceglue project doesn't attempt to teach VXML porgramming.
I realize that there may be a need for such a service, however
that is not voiceglue's purpose.

You can find answers to this particular question here:

   http://www.w3.org/TR/voicexml20/#dml3.1.2
   http://www.w3.org/TR/voicexml20/#dmlABuiltins

Doug Campbell