Stream logs of all containers in pod

[dtan4]

Close #2

WHY

If pod has multiple containers, k8stail cannot print logs of all containers and aborts right away.

WHAT

Stream logs of all containers. Log line includes both pod name and container name.

$ k8stail -timestamps
Namespace: default
Labels:
----------
Pod counter has detected
[counter][count-a] 2016-11-16T02:08:24.081684592Z  | A 4: Wed Nov 16 02:08:24 UTC 2016
[counter][count-a] 2016-11-16T02:08:25.083563263Z  | A 5: Wed Nov 16 02:08:25 UTC 2016
[counter][count-b] 2016-11-16T02:08:24.319290508Z  | B 4: Wed Nov 16 02:08:24 UTC 2016
[counter][count-b] 2016-11-16T02:08:25.321003404Z  | B 5: Wed Nov 16 02:08:25 UTC 2016
[counter][count-a] 2016-11-16T02:08:26.085620721Z  | A 6: Wed Nov 16 02:08:26 UTC 2016
[counter][count-b] 2016-11-16T02:08:26.322793031Z  | B 6: Wed Nov 16 02:08:26 UTC 2016