Improve printing

src/main/scala/leon/purescala/Definitions.scala

src/main/scala/leon/purescala/PrettyPrinter.scala

src/main/scala/leon/purescala/ScalaPrinter.scala

src/main/scala/leon/repair/RepairPhase.scala

src/main/scala/leon/repair/Repairman.scala

src/main/scala/leon/synthesis/SynthesisPhase.scala

src/main/scala/leon/utils/FileOutputPhase.scala