Documented Trees#Identifier and added ADTDefinition transform

src/main/scala/inox/ast/TreeOps.scala

src/main/scala/inox/ast/Trees.scala

src/main/scala/inox/datagen/ModelEnumerator.scala

src/main/scala/inox/datagen/SolverDataGen.scala

src/main/scala/inox/evaluators/RecursiveEvaluator.scala

src/main/scala/inox/grammars/ClosureGrammars.scala

src/main/scala/inox/grammars/ExpressionGrammars.scala

src/main/scala/inox/grammars/ValueGrammars.scala

src/main/scala/inox/grammars/utils/Helpers.scala

src/main/scala/inox/solvers/ADTManagers.scala

src/main/scala/inox/solvers/smtlib/CVC4Target.scala

src/main/scala/inox/solvers/smtlib/SMTLIBTarget.scala

src/main/scala/inox/solvers/smtlib/Z3Target.scala

src/main/scala/inox/solvers/theories/BagEncoder.scala

src/main/scala/inox/solvers/theories/StringEncoder.scala

...main/scala/inox/solvers/unrolling/DatatypeTemplates.scala

...main/scala/inox/solvers/unrolling/FunctionTemplates.scala

src/main/scala/inox/solvers/unrolling/LambdaTemplates.scala

...cala/inox/solvers/unrolling/QuantificationTemplates.scala

...main/scala/inox/solvers/unrolling/TemplateGenerator.scala