[readme] Errors/Incomplete documentation about nano

[dscape]

Yup all true. Documentation is as minimalistic as nano, but in this it's too much.

Also missing is the fact that non 200 codes are sent as errors in the couch scope.

Mind to fork it and do a pull request? :)

[Raynos]

Lazy.

I'll fix your docs after I've used nano some more. Refactoring some request code to use nano

[dscape]

@Raynos first thanks. It's awesome to tell us what needs to be better but
would be even better if you could just fix those things. That's what open
source is all about :)

Code is in heavy refactor mode in the browser branch. We are working on
porting nano to the browser right now. Please check that before any
refactoring so we don't loose out on the awesome stuff you are working on!