convert nearly all of Instruction to Scala

leaving in Java for now: public fields we access in tight inner loops
Merge pull request #586 from NetLogo/scalify-instruction

convert nearly all of Instruction to Scala
reformatting in ExpressionParser

trying to bring the level of hair-raising-ness down from 11
to say 10.8 or so
reformat TestLabels.scala
shorten some irritatingly long test names
Merge branch 'headless' into sbt-0.13.2
upgrade to sbt 0.13.2-RC3