feat : use aliase in Riemann service (for human read) and put all aliases to Riemann tags
feat : add network stats
feat : add CPU User and System
feat : add parameter riemann_host_event

By default, attr host in a riemann event is the hostname of gorycAdvisor when
it is running in a Docker containers. It is not very usefull, so that, we
can force host attr (for example : put hostname of the docker daemon)
fix : using attr
feat : add Memory Usage in Human
feat : add CPU Percent
doc : new parameter riemann_host_event
doc : RIEMANN_HOST_EVENT is optional
Merge pull request #3 from docktor/master

New parameter (riemann_host_event), Network Event