Add Kwapi pollster (energy monitoring).

Given that my blueprint is not publicly available, I summarize it here.

Kwapi (kilowatt API) contains the following modules:
- Drivers: receive values from wattmeters and forward them on a bus (ZeroMQ).
Wattmeter drivers are specific to each wattmeters (Wattsup, OmegaWatt, etc).
- Plugins: listen the bus and process received data.
Currently, there is two plugins: the ceilometer plugin (REST API) and a visualization plugin (build graphs with RRDtool).

Kwapi is part of the XLcloud project (HPC cloud).
http://www.xlcloud.org

Repository:
https://github.com/stackforge/kwapi

Change-Id: Ieaaa1db9c8c569b6ee9f0815e03879f8b3f3e282
Merge "Add Kwapi pollster (energy monitoring)."