Move babel and other command line dependencies to devDependencies

[lewchuk]

It looks like inclusion of babel-cli and the babel-preset-* packages in dependencies adds 45 MB (almost 50%) to the production dependencies of anyone including this library in their dependencies.

Currently:

> yarn install --production
> du -sh node_modules
145M	node_modules

After moving babel-* to devDependencies:

> yarn install --production
> du -sh node_modules
106M	node_modules

Moving the babel packages to dev-dependencies still lets anyone run the command line version of the code when only yarn install --production.

[lewchuk]

Not sure between yarn.lock and package-lock.json how the dependencies are managed otherwise I'm happy to open a PR.

[atlanteh]

Basically if you move the dependencies to to dev-dependencies and run "npm install" & "yarn install" I think these files should be updated automatically.