[Proposal] Change devtool from eval to eval-source-map

[canibanoglu]

Hello,

I've been using this boilerplate to create toy projects to explore tools and each time I find myself fixing up the devtool option for webpack so that I can debug my own source code in Chrome.

I assume many people are also including the source-map option, mainly because most of the issues opened here with webpack configurations seem to have it set.

I would be more than happy to create a pull request for this.

Cheers,

Can

[calesce]

We went with cheap-module-eval-source-map as the best tradeoff in source-map quality and compilation time.