Analysis/Verification now returns a report.

src/main/scala/leon/Reporter.scala

src/main/scala/leon/Settings.scala

src/main/scala/leon/plugin/AnalysisComponent.scala

src/main/scala/leon/plugin/LeonPlugin.scala

src/main/scala/leon/verification/Analysis.scala

src/main/scala/leon/verification/VerificationCondition.scala

src/main/scala/leon/verification/VerificationReport.scala

src/test/scala/leon/test/ValidPrograms.scala