Add --cache (eslint & stylelint style)

[jrencz]

Both ESLint and Stylelint use --cache + --cache-location

Eslint creates cache entries like:

{
  "/path/to/file.js": {
    "size":234,
    "mtime":1505831352000,
    "hashOfConfig":"105xr29",
    "results":{
      "filePath":"/path/to/file.js",
      "messages":[],
      "errorCount":0,
      "warningCount":0
    }
  }
  ...
}

Stylelint has a bit smaller object:

{
  "/path/to/file.scss": {
    "size":541,
    "mtime":1503311672000,
    "hashOfConfig":"ch65yk"
  }
  ...
}

I haven't checked but those are similar enough that I think they either use the same package or one was inspired by another.

Let's discuss a possibility of adding those in here as well