Added upgrade notice to readme
Merge branch 'master' of github.com:dannyvankooten/wordpress-recent-facebook-posts

# By Daniel Foote
# Via Daniel Foote (1) and Danny van Kooten (1)
* 'master' of github.com:dannyvankooten/wordpress-recent-facebook-posts:
  When getting a list from Facebook, don't include "picture" twice in the fields, to prevent the error "Syntax error "Field picture specified more than once. This is only possible before version 2.1" at character 48: id,picture,type,from,message,status_type,picture,object_id,name,caption,description,link,created_time,comments.limit(1).summary(true),likes.limit(1).summary(true)" from the API.