Added a summary of our approach in "Emerging approaches"
 highlighted the two layers of abstraction there
Added key topics to the discussion section
 fleshed out the two layers: semantics specification nd performance control
 ported the perf controls section from the outline
 augmented the treatment of language interface issues
 listed other areas to add, like low-hanging fruit, but haven't yet done so
Listed some areas to add to research areas, but haven't yet done so