trailing spaces
fixes for `tutv_social_media_icons()`

- fixes numerous php notices about missing parameters
by using null default

- fixes incorrect usage of `in_array()` by removing
array support altogether (it's never used)
fix undefined variable for get_video_thumbnail()
fix deprecated WP_Query param `caller_get_posts`

replace with `ignore_sticky_posts`
replace deprecated wp_specialchars with esc_html