Fix Java swigReleaseOwnership() and swigTakeOwnership() regression

Fixes segfault when using non-director classes.
Restores a dynamic_cast which was previously removed.
The dynamic_cast is not needed for the swig_connect_director call ...
we'll have to find another solution for #449 for Java.

Closes #1184

Examples/test-suite/java/director_ownership_runme.java

@@ -0,0 +1,42 @@
+import director_ownership.*;
+
+public class director_ownership_runme {
+
+  static {
+    try {
+      System.loadLibrary("director_ownership");
+    } catch (UnsatisfiedLinkError e) {
+      System.err.println("Native code library failed to load. See the chapter on Dynamic Linking Problems in the SWIG Java documentation for help.\n" + e);
+      System.exit(1);
+    }
+  }
+
+  public static void set_content_and_release(Container container, ContentBase content) {
+    content.swigReleaseOwnership();
+    container.set_content(content);
+  }
+
+  public static void main(String argv[]) {
+
+    Container container = new Container();
+
+    // make a content in java (cMemoryOwn true)
+    ContentBase content_java = new ContentDerived();
+
+    // make a content in c++ (cMemoryOwn true)
+    ContentBase content_cpp = director_ownership.make_content();
+
+    set_content_and_release(container, content_java);
+    if (!container.get_content().get_name().equals("ContentDerived"))
+      throw new RuntimeException("did not get ContentDerived");
+
+    // when swigReleaseOwnership() is called on content_cpp, swig tries a static_cast to director and calls the method
+    // director->swig_java_change_ownership. The content created in c++ native library is not a director, therefore a
+    // segfault may occur.
+    // With a check done using dynamic_cast this issue could be avoided.
+    set_content_and_release(container, content_cpp);
+    if (!container.get_content().get_name().equals("ContentDerived"))
+      throw new RuntimeException("did not get ContentDerived");
+  }
+}
+