CR-4202 Fix for OPENIG-218: Document support for OpenIG as OAuth 2.0 client

git-svn-id: https://svn.forgerock.org/openig/trunk@476 dbb9e58e-28e6-4ce0-90e8-f11d9605b710
CR-4206 Partial fix for OPENIG-229: Prepare release notes

git-svn-id: https://svn.forgerock.org/openig/trunk@478 dbb9e58e-28e6-4ce0-90e8-f11d9605b710
CR-4207 OPENIG-260: Fixes for review comments on the reference

git-svn-id: https://svn.forgerock.org/openig/trunk@480 dbb9e58e-28e6-4ce0-90e8-f11d9605b710