Tests for nav-left/-right/-up/-down CSS 3 UI properties

New and complete set of 64 tests for CSS 3 UI nav-left, nav-right, nav-up and nav-down properties. Adapted and extended from original tests submitted by Opera. I believe all normative assertions from the spec are tested. All tests passed by Opera TV Emulator and build of Chomium submitted by Samsung to the CSS WG. Reviews requested please :-)

Daniel Glazman