And also the package.json which, for reasons I'm not going to spend
the next two hours of my life wading through the electron-builder
source to discover, is no longer automatically included after adding
the files pattern. The node_modules folder is handled automatically
though, so is redundant.
Change the output directory structure so we have one directory with
all the built native modules under that we can just add to the files,
rather than having to add each one separately.
NB. electron-builder add its own filters to node_modules so that only
runtime (ie. not devDependencies) are copied. These seem to apply
even for manually specified path within node_modules. We can copy *to*
the node_modules directory, however...
