Add http input

Due to how traffic interception works, there is chance of missing requests. If you want guarantee that requests will be replayed you can use http input, but it will require changes in app as well. 

```
sudo gor --input-http :28019 --output-http "http://staging.com"
```

Then in your application you should send copy (e.g. like reverse proxy) all incoming requests to Gor http input. 

Fixes #45