grim/convey

Change TaskTimeout to PlanTimeout and show elapsed time on stage finish. Fixes #134
tasks:
normal:
image: nginx:alpine
detach: true
health-check:
image: nginx:alpine
detach: true
healthcheck:
interval: 1s
timeout: 3s
command: wget -O - http://localhost
plans:
default:
stages:
- tasks:
- normal
- tasks:
- health-check