JET-34 Require a return statement in a function with a block body

JET-77 Require a return type annotation for non-Unit returning functions with block bodies

idea/tests/org/jetbrains/jet/codegen/PatternMatchingTest.java

@@ -57,7 +57,7 @@ public class PatternMatchingTest extends CodegenTestCase {
     }
 
     public void testNoReturnType() throws Exception {
-        loadText("fun foo(x: String) = when(x) { is * => return \"x\" }");
+        loadText("fun foo(x: String) = when(x) { is * => \"x\" }");
         Method foo = generateFunction();
         assertEquals("x", foo.invoke(null, ""));
     }