Consolidated all OAuthServiceMetaData in order to create a uniform inheritance hierarchy, remove duplicate code and provide a consistent property naming structure.

linkedinoauth.properties
--------------------------------
-com.openexchange.socialplugin.linkedin.apikey=REPL ACE_THIS_WITH_THE_KEY_FROM_YOUR_LINKEDIN_APP
-com.openexchange.socialplugin.linkedin.apisecret=R EPLACE_THIS_WITH_THE_SECRET_FROM_YOUR_LINKEDIN_APP

+com.openexchange.oauth.linkedin.apiKey=REPLACE_TH IS_WITH_THE_KEY_FROM_YOUR_LINKEDIN_APP
+com.openexchange.oauth.linkedin.apiSecret=REPLACE _THIS_WITH_THE_SECRET_FROM_YOUR_LINKEDIN_APP

twitteroauth.properties
------------------------------
-# The consumer key
-com.openexchange.twitter.consumerKey=INSERT_YOUR_C ONSUMER_KEY_HERE

-# The consumer secret
-com.openexchange.twitter.consumerSecret=INSERT_YOU R_CONSUMER_SECRET_HERE

+# The consumer key
+com.openexchange.oauth.twitter.apiKey=INSERT_YOUR _CONSUMER_KEY_HERE

+# The consumer secret
+com.openexchange.oauth.twitter.apiSecret=INSERT_Y OUR_CONSUMER_SECRET_HERE

facebookoauth.properties
----------------------------------
-# Specify the API key obtained from facebook
-com.openexchange.facebook.apiKey=INSERT_YOUR_API_K EY_HERE

-# Specify the secret key obtained from facebook
-com.openexchange.facebook.secretKey=INSERT_YOUR_AP I_SECRET_HERE

+# Specify the API key obtained from facebook
+com.openexchange.oauth.facebook.apiKey=INSERT_YOU R_API_KEY_HERE

+# Specify the secret key obtained from facebook
+com.openexchange.oauth.facebook.secretKey=INSERT_ YOUR_API_SECRET_HERE