Add a forward declaration

git-svn-id: http://gtm-oauth2.googlecode.com/svn/trunk@119 22754eea-fc93-e339-b032-c1f495b90c16
Allow authorizing file URLs; assert in debug builds on lack of user ID or email address in a retrieved profile

git-svn-id: http://gtm-oauth2.googlecode.com/svn/trunk@120 22754eea-fc93-e339-b032-c1f495b90c16