Merge pull request #1333 from OpenSocial/251_staging

Merge 251 staging into trunk (remove draft tags, prepare final draft)
Add OpenSocial 2.5.1 folder
Merge pull request #1335 from OpenSocial/251_staging

Add OpenSocial 2.5.1 folder
Update 2.5.1 info
Merge pull request #1336 from OpenSocial/master

Publish 2.5.1 changes to Github pages