Repair synthesis after Path refactoring

src/main/scala/leon/synthesis/Problem.scala

src/main/scala/leon/synthesis/Witnesses.scala

src/main/scala/leon/synthesis/rules/ADTSplit.scala

src/main/scala/leon/synthesis/rules/CEGISLike.scala

src/main/scala/leon/synthesis/rules/DetupleInput.scala

...scala/leon/synthesis/rules/GenericTypeEqualitySplit.scala

src/main/scala/leon/synthesis/rules/InequalitySplit.scala

src/main/scala/leon/synthesis/rules/IntroduceRecCalls.scala

...main/scala/leon/synthesis/strategies/ManualStrategy.scala