Merge pull request #241 from khanduri/jb-development

Support for facebook and linkedin usernames.

> Low risk. Isolated. Will create new issue to reference these new variables in the next release.

Author: groundh0g

_config.yml

@@ -16,6 +16,8 @@ author :
   email : blah@email.test
   github : username
   twitter : username
+  facebook : username
+  linkedin : username
   feedburner : feedname
 
 # The production_url is only used when full-domain names are needed