Update README.md

* link to doc.supybot.aperio.fr
* use SSL with IRC links
* link to homepages of freenode/oftc instead of having IRC links to
networks without channels which just confuse users
Anonymous: fix config help for allowPrivateTarget

I am again unsure of my wordings, so if someone could check them, that
would be nice.
Channel: Let ops see nicks in a private channel. Closes GH-797.
Merge pull request #829 from Mkaysi/readme

Update README.md
Merge pull request #851 from Mkaysi/anonymous

Anonymous: fix config help for allowPrivateTarget
Fix 5ff7b83fdd74bc9f5aaeca6d2289dfdb87ab5994.