1.17.4:

* New classes wrapped:
  - Glom::DbUtils
  - Glom::LayoutItem_Notebook
  - Glom::LayoutItem_CalendarPortal
  - Gnome::Gda::Value (minimal support only)
* Enable Glib::ustring reference parameters
* Require libglom >= 1.18.5 for:
  - Glom::LayoutItem_Portal::get_suitable_table_to_view_details()
  - Glom::DbUtils::layout_field_should_have_navigation()
* Better error message when loading the JNI shared library fails.
* Recompile the test when the test source code changes. (Murray Cumming)
* Make all JNI method call synchronized to enable multi-threaded access