use 'rfc' role to link to the RFCs; this fixes one link, for free
update some links and fix others
fix link
update link
use cross-references to fix some links

Also fix grammar, and add a bit of consistency regarding formatting.
make it clear where the link goes
fix links
update links
fix broken link
rm broken link; could not find existing equivalent
fix broken links
rm reference to broken link
we want to keep the reference alive
Merge pull request #885 from tshepang/hyperlinks

fix/update hyperlinks