So, rather than dogfood off of the current working version, I thought it would be nicer to dogfood off the last stable version, via `grunt-es6-module-transpiler`.

This is all well and good in theory, but NPM refused to install `es6-module-transpiler` as a dependency of `grunt-es6-module-transpiler` because `es6-module-transpiler` was, after all, the parent package. Thus, that hacky little line forces NPM to install `es6-module-transpiler` from NPM for the grunt plugin.