Apply BSD 2 clauses license

...sources/regression/verification/xlang/valid/Nested9.scala

...urces/regression/verification/xlang/valid/NestedVar.scala

...esources/regression/verification/xlang/valid/While1.scala

...esources/regression/verification/xlang/valid/While2.scala

...esources/regression/verification/xlang/valid/While3.scala

src/test/scala/leon/test/TestUtils.scala

src/test/scala/leon/test/evaluators/EvaluatorsTests.scala

src/test/scala/leon/test/purescala/DataGen.scala

src/test/scala/leon/test/purescala/LikelyEq.scala

src/test/scala/leon/test/purescala/LikelyEqSuite.scala

...t/scala/leon/test/purescala/TreeNormalizationsTests.scala

src/test/scala/leon/test/purescala/TreeOpsTests.scala

src/test/scala/leon/test/purescala/TreeTests.scala

src/test/scala/leon/test/solvers/TimeoutSolverTests.scala

src/test/scala/leon/test/solvers/z3/FairZ3SolverTests.scala

.../scala/leon/test/solvers/z3/FairZ3SolverTestsNewAPI.scala

...ala/leon/test/solvers/z3/UninterpretedZ3SolverTests.scala

src/test/scala/leon/test/synthesis/AlgebraSuite.scala

...test/scala/leon/test/synthesis/LinearEquationsSuite.scala

src/test/scala/leon/test/synthesis/SynthesisSuite.scala