[0.0.8] Add Config class for rendering and validating config data

Hi,

This patch adds a Config class for rendering and (poorly, but on some level) validating a config file. The motivation was originally for use in the Chef cookbook we just wrote for InfluxDB, which uses a variant on this. At some point I could see this also checking that the correct parameters were used, or maybe even handling the writing of the file to disk. I haven't thoroughly tested this; but here's the output from the builtin suite:

```
Finished in 0.02363 seconds
11 examples, 0 failures
```

I'm gonna add a test or two to this to verify its functionality since obviously there's no real coverage yet, but hopefully it seems alright ... thank you for any feedback!