docker-stats: container realtime performance

Help make this a reality! Vote for docker-stats @ Docker Global Hack-a-thon - 
https://www.docker.com/community/globalhackday/0/ . 

![1-4 copy](https://cloud.githubusercontent.com/assets/9376831/4878164/8761d590-6303-11e4-9db8-60511d34428e.jpg)






```docker-stats``` brings native performance metrics to Docker. Three primary goals:
1) Command Line Docker Metrics
![screen shot 2014-11-02 at 2 35 15 pm](https://cloud.githubusercontent.com/assets/9376831/4877197/96b49f50-62e0-11e4-818d-e13b5df07744.png)


2) RESTful API
- Ease of streaming performance metrics directly via Docker API
- Leverage time series best practices to reduce overhead

Example:
```
{
  "id": "384d38fy48ff",
  "startdatetime": "2014-11-02-HHMMSS",
  "stats": {
    "cpuacct.usage": [
      0001,0002,0003,0004,0005,0006,0007,0008,0009,0010
    ],
    "memory.usage_in_bytes": [
      0001,0002,0003,0004,0005,0006,0007,0008,0009,0010   
    ],
    "blkio.in_service_bytes": [
      0001,0002,0003,0004,0005,0006,0007,0008,0009,0010    
    ]
  }
}
```

3) Ease of integration
Enable the community to add metrics via go interface
Easy to move data via serializable JSON