Disable Host Check

[dmarcos]

It seems that WebPack tightened the security and the dev workflow I'm used to does not work anymore.
npm start and visiting localhost:8080 locally or the ip.of.my.server:8080 from a machine in my network returns an Invalid Host header error message. This PR disables the security host check on the package.json and everything works as it used to on my Windows boxes. The implications go a bit over my head so feel free to suggest an alternative. I found some literature here:

webpack/webpack-dev-server#887
webpack/webpack-dev-server#147 (comment)

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[dmarcos]

I signed it!

[googlebot]

CLAs look good, thanks!

[jsantell]

I ran into this as well -- thanks!