Bump up to version 0.15.0
Bump up to version 0.15.0

This version adds the private url parameter to the loading API.

pudo/spendb,pudo/spendb,CivicVision/datahub,nathanhilbert/FPA_Core,USStateDept/FPA_Core,johnjohndoe/spendb,openspending/spendb,openspending/spendb,johnjohndoe/spendb,pudo/spendb,spendb/spendb,openspending/spendb,CivicVision/datahub,USStateDept/FPA_Core,johnjohndoe/spendb,CivicVision/datahub,USStateDept/FPA_Core,nathanhilbert/FPA_Core,spendb/spendb,spendb/spendb,nathanhilbert/FPA_Core