Merge pull request #3 from thiasB/0.2.1

fixes and version bump

Derive InfluxDB database and measurement from dev_id and signal data …

…from all gateways (#2)

* Dictionaries do not have iteritem methods in 3.x.

* derive InfluxDB data base and measurement from dev_id

* simplify dev_id quartering

* update documentation

* close http session and delete InfluxDB object after sending data

* store LoRa signal data from all receiving gateways

* minor polishing

* rename field names of LoRa signal data

* add Spreading Factor and Bandwidth

* pass integer variables as a list

* add /build to gitignore

* (re)introduce database and measurement from cmd options. new 'split from MQTT topic' option

* update README

* minor optimization

* check for required options

* optional: disable saving geolocation of gateways

* bump version

* harmonize README

* fix missing key for gateway geolocation data

Bump version