added facebook app configure for sdkbox
added facebook app configure for sdkbox

Added like to a blog post where it is details are mentioned to configure the facebook app that supports all features provided within sdkbox for facebook plugin.
sdkbox-doc/en,sdkbox-staging/en,sdkbox-doc/en,sdkbox-staging/en,yinjimmy/en,sdkbox-doc/en,sdkbox-staging/en,yinjimmy/en,sdkbox-doc/en,yinjimmy/en,yinjimmy/en,sdkbox-staging/en