TypeError: configFiles.forEach is not a function

when running mocha-selenium:

`TypeError: configFiles.forEach is not a function
at Object.resolveFiles (/usr/local/lib/node_modules/mocha-selenium/lib/utils.js:55:15)
at Object.Runner.execute (/usr/local/lib/node_modules/mocha-selenium/lib/runner.js:53:11)
at Object. (/usr/local/lib/node_modules/mocha-selenium/bin/mocha-selenium.js:21:21)
at Module._compile (module.js:409:26)
at Object.Module._extensions..js (module.js:416:10)
at Module.load (module.js:343:32)
at Function.Module._load (module.js:300:12)
at Function.Module.runMain (module.js:441:10)
at startup (node.js:139:18)
at node.js:968:3
Stratos-MacBook-Pro:selenium stratos$`

I am assuming I have a mistake in my config file but the whole setup would be easier with a simple test example since the documentation is sparse :(

my selenium config file:

```
{
"files": "first.js",
"envs": {
"local": ["internet explorer", "8", "Windows XP"]
}
}
```

Start with the stack-trace locations in lib/utils.js, lib/runner.js, and bin/mocha-selenium.js, then inspect how the shown configuration is loaded. Reproduce the TypeError with the provided config and determine the expected shape of files; done means the example setup runs without this error and the configuration expectation is clear.

Written by the indexing model from the issue text.