Project environment clobbers parent

[RealOrangeOne]

$ DATABASE_URL="not a database url" crab env | grep DATABASE               
DATABASE_URL=postgres://localhost/db

crab should only set environment variables when they're not defined in the project itself. I think?

[j4mie]

I think it should override existing ones.. that's kinda the point isn't it?

[RealOrangeOne]

I can't think of a time i'd want a project to override its parent environment. And it's also really useful to be able to override variables as above