document common query types. 
document common query types. 
openspending/spendb,nathanhilbert/FPA_Core,USStateDept/FPA_Core,johnjohndoe/spendb,CivicVision/datahub,nathanhilbert/FPA_Core,openspending/spendb,spendb/spendb,pudo/spendb,spendb/spendb,pudo/spendb,openspending/spendb,nathanhilbert/FPA_Core,johnjohndoe/spendb,spendb/spendb,USStateDept/FPA_Core,USStateDept/FPA_Core,CivicVision/datahub,CivicVision/datahub,johnjohndoe/spendb,pudo/spendb