Fix 'New Topic' anchor for group forums using bbPress 1.x.

Boo Ray.
Add 'bp_head' hook to CBOX Theme.

The 'bp_head' hook is hardcoded in bp-default's header.php.

Since CBOX Theme / Infinity uses bp-default templates as a base, we also
need to add this hook b/c BP and BP plugins use it to add items to the
<head>.

See #131.
Show BP Courseware item-list-tabs. See #131.