add to the solution matrix

From the 5/24 TC minutes:
> DITA 1.3: Michael Priestley summarized some thoughts that he has been having about building into DITA 1.3 a template-based interface against a subset of DITA features that would allow users to pick and choose what they would like to see included in a constraint. This completed template could be exported to multiple tool environments. - A dedicated working group would be one approach to getting this done. Should we add something about this to the solution matrix now? No action was specifically identified. (This is not an amendment or addendum to the minutes.) /B