Closing implementation issues

Dear all,

I made some progress on some implementation issues

  * https://github.com/w3c/voiceinteraction/issues/56 Add chaining of
    filters to select an IPA Provider
  * https://github.com/w3c/voiceinteraction/issues/55 Consider Languages
    in Reference Implementation
  * https://github.com/w3c/voiceinteraction/issues/54 Make OpenAI access
    configurable

As per my understanding they can be closed. Do we need to review them in 
our next call or shall I close them right away?

Please, also feel free to check my changes in case you want to comment 
on the coding.

Dirk