added cadvisor meter for host and services

[finishes: #80456090]

![screen shot 2014-10-14 at 2 11 22 pm](https://cloud.githubusercontent.com/assets/923211/4635062/f8d74fda-53d5-11e4-9ab1-6dd3650c2373.png)

Yeah, if I'm following along correctly, It seems more natural to have a ```HostHealthController#show``` and ```ServiceHealthController#show```