[skip ci] Commit black code style formatting

Only submit 3.7 coverage (as we don't do a full run elsewhere)

Merge pull request ibm-watson-iot#169 from ibm-watson-iot/destination…

…Retention

Add dsc connector type and destination retention time

Merge pull request ibm-watson-iot#147 from ibm-watson-iot/deviceFacto…

…rySample

Add publish event sample to docs

Merge pull request ibm-watson-iot#140 from ibm-watson-iot/dockertest

Dockertest

Merge branch 'master' of https://github.com/ibm-watson-iot/iot-python

Fix up messageLock logic for pub callback handling

ibm-watson-iot#122

Prepare for 0.4.0 release

Hopefully a proper 1.0 release isn't too far off now ...

added sample thing config

[patch] First pass at subscription handling in gateway

ibm-watson-iot#86