undefined notices in the customizer preview fixed

-- Debug: Undefined index: options on line 662 of /wp-content/themes/duena/options.php
-- Debug: Undefined index: options on line 816 of /wp-content/themes/duena/options.php
-- Debug: Undefined index: options on line 1004 of /wp-content/themes/duena/options.php
-- Debug: Undefined index: options on line 1074 of /wp-content/themes/duena/options.php
-- Debug: Undefined index: options on line 1102 of /wp-content/themes/duena/options.php
-- Debug: Undefined index: pblog_sidebar_pos on line 1122 of /wp-content/themes/duena/options.php
-- Debug: Undefined index: options on line 1253 of /wp-content/themes/duena/options.php
Merge branch 'master' of https://github.com/DuenaStudio/DuenaTheme