Interwiki support

[Marco Pesenti Gritti <mpg redhat com>]

Hi,

so I was going to implement interwiki support but, after discussing it
with alex, I think we should change perspective a bit on this.

Alex correctly pointed out that supporting a markup format somewhat
force the users to learn it and introduce complexity.

<alex> say the user wants to say "array[i] = x"
<alex> suddenly all chat lines and comments must be some valid markup
format...
<alex> That increases the complexity of using it a bit

So we tried to think about ways of linking to interwiki topics in a more
user friendly way.

1 Users could copy the web address of the wiki page they are visiting
and paste it in the chat. It would be good to show such addresses as a
link with a meaningful title.

Examples:

http://live.gnome.org/NewDefaultTheme -> [NewDefaultTheme on GNOME wiki]

http://bugzilla.gnome.org/show_bug.cgi?id=172800 -> [GNOME bug 172800]

2 We could parse real language phrases and highlight them as links. This
is more natural and doesnt introduce the issues of a markup language.

Examples:

bug 172800 -> link to http://bugzilla.gnome.org/show_bug.cgi?id=172800

NewDefaultTheme wiki -> link to http://live.gnome.org/NewDefaultTheme

(in the context of the GNOME yarrr server)

We could just store a list of these substitutions on the server and
apply them to the text. The current [WikiTopic] substitution could just
be a special case, it could be used on yarrr servers where learning a
basic markup language is supposed to be easy/useful for users (for
example gnome.org yarrr).

One open question is where to do the substitution. Doing it on the
server is going to be more complex and doesnt seem provide advantages
for this use case. Though it could make sense if we are going to need to
use a markup language for the server text content for other reasons...

I think I'm going to do this client side for now, though the format the
server use to provide content is something we need to discuss.

Marco