fixes for the build process

See #8
> But people are so lazy :)
> So I'm not sure is a good idea to do it (remove MANIFEST) in the such case.

Yeah, but letting them not update the manifest means they'll be lazy and forget to do it ;)

Manifests should either be a) 100% automatic  or b) 100% manual.

Anything in between is going to basically be hoping somebody remembers to do it when its required, which, they wont.