Multiple bug fixes

【Contents of the fix】
■SSL support for the “Google Custom Search” widget.
■Fixed a bug that the text color of catchphrase in each item is not reflected in the setting of TCD Theme > Top Page > Header Content.
■Fixed a bug that “Setting the speed at which the slider switches” is not reflected in the setting of TCD Theme > Top Page (for smartphone) > Header Content.
■Fixed an error when hiding banner contents 1 and 2 in TCD Theme > Footer > Banner Contents settings.

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

【Modified file】
footer.php
functions/head.php
functions/slider_ini.php
functions/update_notifier.php
languages/ja.mo
languages/ja.po
style.css
widget/google_search.php