Extended termination to HO functions

src/main/scala/leon/purescala/TypeTrees.scala

src/main/scala/leon/solvers/z3/Z3ModelReconstruction.scala

src/main/scala/leon/termination/ChainBuilder.scala

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

src/main/scala/leon/termination/ChainProcessor.scala

src/main/scala/leon/termination/LoopProcessor.scala

src/main/scala/leon/termination/RelationBuilder.scala

src/main/scala/leon/termination/RelationProcessor.scala

src/main/scala/leon/termination/Strengthener.scala

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

...sources/regression/termination/looping/Looping1.scala.BAK

...sources/regression/termination/looping/Looping2.scala.BAK

...sources/regression/termination/looping/Looping3.scala.BAK

...esources/regression/termination/valid/HOTermination.scala

...sources/regression/termination/valid/HardChains.scala.BAK

...rces/regression/verification/purescala/valid/Lists2.scala