reduce test output
z3 backed execution inspired by Leon

implementing the guarded unfolding logic for recursive
functions from this paper:

"Satisfiability Modulo Recursive Programs"
http://lara.epfl.ch/~kuncak/papers/SuterETAL11SatisfiabilityModuloRecursivePrograms.pdf
generalize: Rel=Exp[Bool]
z3 generates quines (but takes ~25s) /cc @namin
Update to Scala-Virtualized 2.10.2.
update mac os x instructions
extra mac prefix no longer necessary, now that extension is fixed
add build.properties for sbt to work well with new scala-virtualized
Option monad! unfortunately big slowdown (200s)
perf debugging. down to 5s

things that make a difference:
- the random seed passed to z3 (!)
- the way we emit path conditions (only last cond vs
  conjunction of all conds and let-insertion vs. duplication)

conclusion: seed=0, all conds, duplicate
fix red test. @TiarkRompf -- seems OK to you?
update for z3 rc
mac os x tweaks
detailed setup instructions for Linux and Mac OS X
formatting
formatting try 2
link formatting
sudo fix
extra step
fix typos in cmds