lines 93,96 and 98:
"<script src=\"http://connect.facebook.net/en_US/all.js#xfbml=1\"> need to be changed to: "<script async src=\"http://connect.facebook.net/en_US/all.js#xfbml=1\">
that is an extremely easy edit and anyone can do this by using the plugin editor and editing the php file for this.
the other issue that also causes low seo ratings and poor results on gtmetrix.com is that you do not have any way to specify image dimensions for post pictures or profile pictures.
please fix the image dimension problem asap, otherwise this is an awesome plugin