working progress in a pass to process array

src/main/scala/leon/ArrayTransformation.scala

src/main/scala/leon/Main.scala

src/main/scala/leon/plugin/CodeExtraction.scala

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

src/main/scala/leon/purescala/Trees.scala

testcases/regression/valid/Array1.scala