* Remove CleanWebpackPlugin
    This pugin would wipe the non-minified files every time `make dist` was called,
    and generally made it more difficult to build only particular files.
* Use order-only prerequisites for the `dist` Make recipe
    This allows more efficient building because order-only prerequisites
    don't force a rebuild of the main recipe.
    https://www.gnu.org/software/make/manual/make.html#Prerequisite-Types