- Removed `detach` argument from `run` and `exec` APIs since it doesn't really make sense to use in a method context. - Added `build` API to create new Docker images, and return a buidl result containing the output of the build as well as the name of the image tagged. - Added API to tag existing images with `Docker.tag(_:source:)`. - Added API to push images to a remote repository with `Docker.push(_:)`. - `Docker.exec` no longer returns the output of the command (because it never worked).