Improve section 7 and update the conclusions to note we've been using
this package at Google for 5 years, not 3 years.  Done with section 7
updates.  6 and 8 need work.



git-svn-id: svn://svn.r-forge.r-project.org/svnroot/rprotobuf@904 edb9625f-4e0d-4859-8d74-9fd3b1da38cb