Events example using TLS for docker daemon 

Hi,

I'm using Boot2Docker on a Mac which uses TLS. How do I configure the certificates for use with the client. 

This is what I need to do using the python client. 

```
tls_config = tls.TLSConfig(
client_cert=('cert.pem', 'key.pem'),
verify='ca.pem')
```

Also I'm getting an error when I run the events exampe.

```
./docker_evnts.go:44: reader declared and not used
```
