Add support for hiding meta box in post editor per taxonomy WP 3.8

http://core.trac.wordpress.org/ticket/21543#comment:12
Fix for User registration required field errors
Support for Custom Comment Types (if the functionality exists on the site via plugin or core update in the future)
Fix help text issue with i18n empty 'help' text
Add pods_array_insert_after and pods_array_insert_before data manipulation functions
More Custom Comment Type support
Move pod / field tabs and options methods from PodsAdmin to PodsObject_Pod; Cleanup field usage in setup-edit.php for some more things that weren't dynamic before