[social_buttons] Update zh_CN, thanks to : dennisyan

git-svn-id: http://piwigo.org/svn/extensions/SocialButtons@21308 68402e56-0260-453c-a942-63ccdbb3a9ee

language/zh_CN/description.txt

@@ -1 +1 @@
-Facebook,Twitter,Google+和Tumblr的分享功能
+Facebook, Twitter, Google+ 和 Tumblr 的分享功能

language/zh_CN/plugin.lang.php

@@ -32,4 +32,7 @@ $lang['Via'] = '经由';
 $lang['Right bubble'] = '右边提示泡';
 $lang['Top bubble'] = '顶部提示泡';
 $lang['Button type'] = '按钮类型';
+$lang['Display buttons'] = '显示按钮';
+$lang['on photo and album'] = '在图片和相册';
+$lang['only on photo'] = '只在图片';
 ?>