default index file in development

[zakpatterson]

Right now we have index.html and index-dev.html. In "production", meaning deployed to github pages, we need index.html. In dev, we're using index-dev.html

So we need a way to make index-dev.html the default in development. At the moment one must explictly go to index-dev.html. This also means reloading / direct url navigation doesn't work.

This line of the configuration is ignored by webpack-dev-server for some reason