* `Env.MultiMap` returns the contents of an Env as `map[string][]string`
* `Env.InitMultiMap` initializes the contents of an Env from a `map[string][]string`
This makes it easier to import and export an Env to other formats
(specifically `beam/data` messages)
Docker-DCO-1.1-Signed-off-by: Solomon Hykes <solomon@docker.com> (github: shykes)
Upstream-commit: c7978c98097b92b659e2ea1763cd134b0695407e
Component: engine