Likes: Added Portfolio Project check to make settings work properly

The Project Likes checkbox in the sharing settings did not have
any effect because the post's custom type was never checked.
Likes: updated the code to accept arbitrary CPTs

This allows enabling and disabling likes for any custom post
type, not only Portfolio Projects as done previously.
Merge pull request #1400 from zinigor/likes/cpt-setting-fix

Likes: Added Portfolio Project check to make settings work properly, props @zinigor. Fixes #1361