Issue #249: first cut at fix

- when imports are created for each of the references, a copy is
  made of the primary project spec, but the copy isn't necessary
  (I think) ... given the fact that we have a project reference
  it makes real sense to combine them all into one load-fest
- the algorithm was using copies from the very beginning and
  I think that was me being conservative ... but with obvious
  performance problems combining makes tons of sense ...