Stands for Vim Elm Helper (yeah, that's cheap)
It's work in progress, for now it can install missing packages, but there is plan for more.
To install missing packages use ElmperInstallMissingPackages command. It looks
for imports in current file and if package providing given module is not installed
it will try to install it. For example if you add import Mouse in new elm file
and run this command it will do elm-package install elm-lang/keyboard --yes.