Add tutorial for stand-alone client application

[Drup]

I know it's possible to have a stand-alone client app that can be used offline, I also know that there are some workaround involved, but afaik there is no documentation about it (except maybe the graffiti code).

Several people asked on irc if it was possible (and I think the "how" is going to come pretty soon).

ping @balat ;)

[balat]

Yes it's still very experimental and we have little experience in this. Someone should take time to test, adapt Eliom if needed, and write a tutorial. @ArnaudParant and @srax used this for writing mobile apps. I think the only think to know is that you must call function Eliom_client.init_client_app to bind the app to a default server (but my goal was to make possible to use Eliom on client side without this).

[Drup]

Ok thanks. At least the information about this Eliom_client.init_client_app is written down somewhere, so I can point people to it. :)