Support more flags in devtoolrc

[ngryman]

Hey,

Context

I'm trying to debug my tests using ava and devtool.
For my project, I've managed to do it like so: NODE_ENV=test devtool node_modules/ava/profile.js test/dfs-pre.js -r babel-register

Note that I need to put devtool flags at the end as profile.js reads arguments at specific positions. That said I use this command line in a npm script to which I pass the file I want to debug.

package.json

{
  "scripts": {
    "debugfile": "NODE_ENV=test devtool node_modules/ava/profile.js -r babel-register"
  }
}

cli

$ yarn debugfile test/dfs-pre.js

result

NODE_ENV=test devtool node_modules/ava/profile.js -r babel-register test/dfs-pre.js

Problem

The problem is that I need my test/foo.js to be the 3rd argument. The flags of devtool conflict with this.

Proposal

In order to be able to start devtool without any flags, it would be super nice to be able to make them available in .devtoolrc. The most urgent for me would be require.

Thanks!