Facilitate applying patches

[stefan-wullems]

We are having problems with browser extensions that interact with a part of the dom that elm is responsible for. The only way I've found I can fix this is by applying the patches provided in this repo: https://github.com/jinjor/elm-break-dom to the virtual-dom library.

Because elm-webpack-loader is responsible for the compilation, I'm having a tough time trying to get this to work.

I can probably hack my way to a solution, but it seems to me a common enough problem to support something to help with this.

Perhaps we could add a patches option, that is an array of objects with the following structure:

{
  patch: "patches/VirtualDom.patch",
  file: "~/.elm/0.19.1/packages/elm/virtual-dom/1.0.2/src/Elm/Kernel/VirtualDom.js"
}