Make tuple manipulation more robust

src/main/scala/leon/codegen/CompilationUnit.scala

src/main/scala/leon/datagen/VanuatooDataGen.scala

src/main/scala/leon/frontends/scalac/CodeExtraction.scala

src/main/scala/leon/purescala/Constructors.scala

src/main/scala/leon/purescala/Extractors.scala

src/main/scala/leon/purescala/TreeOps.scala

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

...main/scala/leon/solvers/templates/TemplateGenerator.scala

src/main/scala/leon/solvers/z3/AbstractZ3Solver.scala

src/main/scala/leon/synthesis/ExamplesFinder.scala

src/main/scala/leon/synthesis/Solution.scala

src/main/scala/leon/synthesis/Synthesizer.scala

src/main/scala/leon/termination/ChainComparator.scala

src/main/scala/leon/termination/StructuralSize.scala

src/main/scala/leon/utils/UnitElimination.scala

src/main/scala/leon/xlang/ImperativeCodeElimination.scala