Multiple bug fixes / feature additions

【Contents of fix】
■Fixed a bug that the eye catching image in mega menu B is also displayed in small size when the article title is short.
■Fixed a bug that the setting of “Show date” in the top page content builder “News” is not reflected.
■Added custom script function.

【Fixed files】
admin/contents-builder.php
admin/inc/basic.php
admin/theme-options.php
functions/head.php
languages/ja.mo
languages/ja.po
style.css