Add protocols.irc.certfile

Fixes #612.
scripts/supybot-plugin-create: Fix #721 .

* README template is now cut to two lines for easier reading in non-word
wrapping text editors on normal terminal size.
* README is now saved as `README.md` instead of `README.txt`.
Mass rename README.txt --> README.md .

[SKIP CI]
.gitignore: add README.txt .

[SKIP CI]
src/conf.py: reword the config help for `reply.oneToOne`.

Suggested by @monodemono on `#supybot`.

**Comments wanted:** does this rewording make sense? If it doesn't, how
could it be better?
Factoids: make more sense with default config.

* Default separator to `is`.
    * It's more used than `as`.
    * Help text updated too.
* Default value as `$value`. Like with Topic plugin, the `$key could be`
is just annoyance which users are very likely to disable anyway.
Factoids: fix tests.
.travis.yml: add check_trans for core too.
core: update messages.pot & l10n-fi.
locales/fi.po: update header.

[SKIP CI]
Factoids: update l10n-fi & messages.pot.
I am Mikaela.

And I thought this was already made clear to Limnoria, but seems that it
wasn't. because the wrong name appears in translations that I don't
remember touching.

[SKIP CI]
Time & User & Web: Fix metadata of translation files.
Alias: improve formatting of README.md.
Anonymous: add another example & add notice about...

...this plugin not meant for identifying even if it's possible and tell
how the identifying should happen.
AutoMode: update README.md.

[SKIP CI]
Merge pull request #729 from Mkaysi/core-l10n-fi

core: update messages.pot & l10n-fi.
Ctcp: Mention channel mode +C in README.
Karma: fix quoting in README.md and one mistake.

* plugins.karma.allowunaddressedkarma doesn't mean that the bot must be addressed by nick. It must be addressed, but that can also happen with prefix.

[SKIP CI]
Lart: fix README.md.

[SKIP CI]