Upgrade Compiling/Packaging to Typescript/Webpack

Created by: hawkinsw

1. Slowly begin migrating code to Typescript from raw Javascript
2. Instead of relying on built-in node module bundling, use webpack
3. Add a yarn watch command that will rebuild mw2pdf when any TS file is edited. (see https://github.com/OpenTechStrategies/torque-devenv/issues/19)

These are prerequisites (in a very yak-shaving way) for adding unit testing to the code via Jest. See https://github.com/OpenTechStrategies/SimpleBook/issues/20.