Initial commit of French translation

package.nw/GridTracker.html

@@ -1200,6 +1200,7 @@ OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
                         <option value="cn">简体中文</option>
                         <option value="cnt">繁體中文</option>
                         <option value="de">Deutsch</option>
+                        <option value="fr">Français</option>
                       </select>
                     </td>
                   </tr>

package.nw/lib/i18n.js

@@ -2,7 +2,8 @@ let languages = {
   en: "i18n/en.json",
   cn: "i18n/cn.json",
   cnt: "i18n/cn-t.json",
-  de: "i18n/de.json"
+  de: "i18n/de.json",
+  fr: "i18n/fr.json"
 };
 
 function loadI18n()