[READY] Allows server to pick up DOCKER_CERT_PATH variable

### Problem

With the latest update of docker to 1.3, SSL is [turned on](https://docs.docker.com/reference/api/docker_remote_api/) by default with the remote API. This breaks the spurious server as it needs to pass the client cert and ca along to the [docker-api](https://github.com/swipely/docker-api) gem when it's setup ([further discussion can be found here](https://github.com/swipely/docker-api/issues/202))

### Solution

By parsing the `DOCKER_CERT_PATH` variable, if it's available then we look for the relevant certs and if they're found we set them as default options on the `Docker.options` method of the [docker-api](https://github.com/swipely/docker-api) class.