Apply BSD 2 clauses license

...urces/regression/verification/purescala/valid/Unit1.scala

...urces/regression/verification/purescala/valid/Unit2.scala

...esources/regression/verification/xlang/error/Array1.scala

...sources/regression/verification/xlang/error/Array10.scala

...esources/regression/verification/xlang/error/Array2.scala

...esources/regression/verification/xlang/error/Array3.scala

...esources/regression/verification/xlang/error/Array4.scala

...esources/regression/verification/xlang/error/Array5.scala

...esources/regression/verification/xlang/error/Array6.scala

...esources/regression/verification/xlang/error/Array7.scala

...esources/regression/verification/xlang/error/Array8.scala

...esources/regression/verification/xlang/error/Array9.scala

...ources/regression/verification/xlang/invalid/Array1.scala

...ources/regression/verification/xlang/invalid/Array2.scala

...ources/regression/verification/xlang/invalid/Array3.scala

...ources/regression/verification/xlang/invalid/Array4.scala

...ources/regression/verification/xlang/invalid/Array5.scala

...rces/regression/verification/xlang/invalid/Epsilon1.scala

...rces/regression/verification/xlang/invalid/Epsilon2.scala

...rces/regression/verification/xlang/invalid/Epsilon3.scala