Doc refresh after Japanese & INSTALL updates

...from Shin-ichi

docs/ja_JP.UTF-8/html/EXTENDING.html

@@ -96,7 +96,7 @@
             </li>
 
             <li>
-              <a href="#fonts">Fonts</a>
+              <a href="#fonts">フォント</a>
             </li>
 
             <li>
@@ -125,7 +125,7 @@
             </li>
 
             <li>
-              <a href="#on_screen_keyboard">On-screen Keyboard</a>
+              <a href="#on_screen_keyboard">画面キーボード</a>
             </li>
           </ul>
         </td>
@@ -657,7 +657,7 @@
         </blockquote>
 
         <h4>
-          Initial Stamp Size        </h4>
+          スタンプサイズ        </h4>
 
         <blockquote>
           <p>
@@ -709,7 +709,7 @@
 
     <h2>
       <a name="fonts"
-          id="fonts">Fonts</a>
+          id="fonts">フォント</a>
     </h2>
 
     <blockquote>
@@ -951,7 +951,7 @@
 
     <h2>
       <a name="on_screen_keyboard"
-          id="on_screen_keyboard">On-screen Keyboard</a>
+          id="on_screen_keyboard">画面キーボード</a>
     </h2>
 
     <blockquote>