Feature/co2

- vol -> kWh is now an automatic job
- Added kWh -> co2 calculation
- Added new jobs to scheduler and made rollups and difference series calculation trigger every 15/20 minutes

Whenever new device is added, or new synthetic sensor created, a set of default sensors should be created, e.g. m^3 sensor should have also sensorType_kWh and sensorType_co2 added (for automatic calculations)
At the moment this is done by having calculated-sensor function in devices.clj:
https://github.com/MastodonC/kixi.hecuba/blob/feature/co2/src/kixi/hecuba/api/devices.clj#L47
which is called when new device is created and when new synthetic sensor is added:
https://github.com/MastodonC/kixi.hecuba/blob/feature/co2/src/kixi/hecuba/api/datasets.clj#L61
This doesn't seem quite right and any suggestions on how to improve it will be appreciated.
I'm OK with these as case statements, but even then I'd probably define maps the then do a get on the map instead. We can leave them for now though.