Man page documentation plugin

[Sven Brauch]

> A bug report sounds great to me...
Well, less great than a patch! ;)

> And yes, maybe we can find a way to give more priority to QtHelp plugin, so
> that we don't get to man, although there will be other cases where it won't
> work.
Which cases for example?
I'll investigate if we can do that.

> We should find a better way (like caching what man pages we have,
> maybe?).
Sorry, I don't get how this would help in ... which case?

Cheers!