Added a set example which is successfully parsed.

(No cardinality extraction, though.)

testcases/SetOperations.scala

+import scala.collection.immutable.Set
+
+// Cardinalities not supported yet.
+// Pre/Post conditions commented out.
+
+object SetOperations {
+    def add(a: Set[Int], b: Int) : Set[Int] = {
+        // require(a.size >= 0)
+        a + b
+    } // ensuring((x:Set[Int]) => x.size == a.size + 1)
+}