Documentation edits

Edit the documentation for minor grammar, idiomatic usage, and sentence construction issues.  Overall the documentation is great;  this is just cleaning up some places that sound a little odd.

There are some notes left in the documentation delimited by [bwb: ...] where I made a larger-than-usual change or I thought needed attention from someone more familiar with the codebase than I am.


For OAuth the authentication information contains the access keys. And with this access keys it is possible to send a new request to the provider to fetch additional data. Now this can be achieved with the social profile builder. Maybe we can remove this sentence?