Master jomsocial

In case of Kunena, like_id has to be equal to the activity id, otherwise a single like action will affect multiple stream entries referring to the same thread. 

For that we need to modify the plugin and the CActivityStream library. 

In next Jomsocial iteration CActivityStream::add() will  be returning a table object, one that can be modified and re-saved. That's what the extra code in the plugin does. The is_object check exists for backward compatibility - in older versions of Jomsocial CActivityStream::add returns nothing, treating it as an object would obviously explode.