Fixed multiple bugs / WP5.0 compatible

【Contents of fixes】
■Support for WordPress 5.0 (Gutenberg)
■Fixed a bug in which videos on the gallery page would remain playing in the background.
■Fixed a bug that only the text can be hidden even if the password is protected in “Gallery” and “Schedule”.
■Delete unnecessary files.

The following files have been fixed in this update.
【Fixed files】
functions/head.php
pagebuilder/pagebuilder.php
pagebuilder/assets/admin/css/admin.css
pagebuilder/assets/admin/js/admin.js
pagebuilder/assets/admin/js/googlemap.js
pagebuilder/assets/css/googlemap.css
pagebuilder/assets/css/pagebuilder.css
pagebuilder/assets/css/slider.css
pagebuilder/assets/js/googlemap.js
pagebuilder/modules/catchcopy.php
pagebuilder/modules/googlemap.php
pagebuilder/modules/headline.php
pagebuilder/modules/image.php
pagebuilder/modules/simpletable.php
pagebuilder/modules/slider.php
pagebuilder/modules/tab.php
language/ja.mo
language/ja.po
single-event.php
single-gallery.php
style.css

【Deleted files】
widget/event_list – copy.php
widget/event_list -corrupted text.php