0.4 23mar2015
* fail hard if unit system is not known

0.3 30jan2015
* added augment_record option

0.2 25jan2015
* fixed typo in install.py: ThingSpeakInstaller not ThinkSpeakInstaller

0.1  06dec2014
* initial release as packaged weewx extension for weewx v3
* added system to specify which observations are uploaded
* added system to specify per-observation labels, units, and formatting
