rake meta::generate_sample_logs

-  generates some sample nginx_combined logs and imports them as test data

After creating a "fresh" vagrant dev vm, running this will give you a kibana with 1 hour's worth of data

![image](https://f.cloud.github.com/assets/227505/1336613/da243376-35c9-11e3-9a9b-df3771de4d6d.png)