Fixed some typos, clarified admin mgmt, vid styles

Fixed some typos, clarified admin mgmt, vid styles

Fixed some words like "Adming" and "Memnber", mostly comments
Added video style change to add some spacing below it on the
member detail page.
Changed the submenu auto-creation to be friendlier toward existing
submenu creation code, and to depend a bit more on functions.php
of the theme.
Reorganized "list" and "detail" page settings in admin side
management.