Request: `electron-rebuild` plugin to use with afterCopy

Currently when packaging cross-arch native node modules I am having to wrap my electron-packager calls with electron-rebuild spawn promise magic ✨

An optimum solution to this issue would be for electron-packager to support a rebuildNativeModules option that would call electron-rebuild while packaging and pass in the correct arch and version parameters.

Example of how to use electron-rebuild can be found in their README and in the cli.js

I’m happy to attempt a PR for this if it is a feature that you guys feel should be part of electron-packager

[reconbot]

If you take a project like node-serialport, I precompile binaries for all platforms and arch’s. I use node-pre-gyp to distribute them in the preinstall hook, and save them in a common location. The other major prebuilt binary package manager prebuild will do the same. Each platform would need the file replaced (not the default behavior) before the package is rebuilt.

I’d gladly work to make the electron precompiled binaries available if they could be used with electron packager.

[unindented]

@malept could you add instructions on how to make the two packages work together nicely?