Find Matches

Added auto finding matches in Wprime, but there are
two areas to develop further;

1. Use the W'bal data to find matches instead of the
   power above CP (which is really being used as a proxy
   for the better approach).

2. Update the 'find intervals' dialog to allow you to
   find matches and add them as normal intervals.

Pushing to repo as a version checkpoint, this function
will definitely need refining before 3.1 is released.