Added some tests and guarded reference equality for lambdas

src/main/scala/leon/solvers/templates/LambdaManager.scala

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

src/main/scala/leon/solvers/templates/Templates.scala

...regression/verification/purescala/invalid/BraunTree.scala

...regression/verification/purescala/valid/FlatMap.scala.BAK

...rces/regression/verification/purescala/valid/Lists5.scala

...ces/regression/verification/purescala/valid/Monads1.scala

...urces/regression/verification/purescala/valid/Sets1.scala

...urces/regression/verification/purescala/valid/Sets2.scala

...rces/regression/verification/purescala/valid/Trees1.scala