- First step for integration of the analytics framework in the collectagent
- QueryEngine and REST API integration still missing
- Proper testing still to be done
- Added a probe function: the global config file is scanned before
initialization, and if no data analytics plugins are requested, no
sensor navigator is built

- A nicer and refactored version of the "average" plugin
- Allows to perform arbitrary aggregation operations over sensors, like
sum, average, or maximum