Fixes
Fixes

- only create iobroker database when not existing, so check before
- correct function needed to be called to drop database.
- InfluxDB can not handle null values, so do not send these values
- added some debug outputs
- rework query method to handle missing query, error responses and
support multi query returns. if commit is accepted I would also add
some documentation in README.md

ioBroker/ioBroker.influxdb