Multiple bug fixes

【Contents of the fix】
■OGP tag optimization
■Changed Facebook OGP setting from old specification (fb:admins) to new specification (fb:app_id).
※Please refer to the following article about how to get “fb:app_id” (application ID).
 How to get the fb:app ID required for Facebook OGP settings
■【Mac】Fixed a bug that the thickness of Japanese and European characters may be displayed differently when using some fonts.
■Fixed an error related to the login judgment in the comment section.
■Social Button Type 5 (Official Button) “Facebook Like Button” specification change.
■Removed the discontinued “Google+” from the social button settings.

The following are the files that have been modified for this update.

【Modified file】
admin/theme-options.php
comments.php
focus.css
functions/ogp.php
functions/seo.php
functions/update_notifier.php
languages/ja.mo
languages/ja.po
sns_btn_btm.php
sns_btn_top.php
style.css
widget/google_search.php