Maybe a better default outline-minor-mode-prefix?

[Lennart Borgman (gmail)]

This is currently "\C-c@". This is a bit awkward to type, at least on a 
Swedish keyboard. It is a rather important binding, since 
outline-minor-mode can be used a lot.

Could maybe "\C-c+" be used instead? This binding is rather mnemonic in 
nature and more easy to type. (And I guess + is easy on any keyboard.)