DIRECTOR: LINGO: Fix memory leak

Memory leak happens when a cast is moved but without
specifying the place for it to move to.
Datum constructor gets the castMemberId by copy leaving the
resource to be dealt with by the original function.

- Includes lingo test.

Fixes COVERITY: 1498924

engines/director/lingo/lingo-builtins.cpp

@@ -2148,6 +2148,7 @@ void LB::b_move(int nargs) {
 		int id = (int) g_director->getCurrentMovie()->getCast()->_castArrayStart;
 		CastMemberID *castId = new CastMemberID(id, 0);
 		Datum d = Datum(*castId);
+		delete castId;
 		g_lingo->push(d);
 		b_findEmpty(1);
 		dest = g_lingo->pop();

engines/director/lingo/tests/builtin.lingo

@@ -11,6 +11,8 @@ open "Hello" && "more" with "Finder"
 move cast 1, cast 1
 move cast 1, 3
 move cast 3, 1
+move cast 1
+
 put findEmpty(cast 10)
 pasteClipBoardInto cast 2
 put the width of cast 1