Add time slider to bubble tree widget. 
Add time slider to bubble tree widget. 
RCGTDev/openspendingjs,openspending/openspendingjs,RCGTDev/openspendingjs,openspending/openspendingjs-old,openspending/openspendingjs,RCGTDev/openspendingjs,openspending/openspendingjs,openspending/openspendingjs-old,RCGTDev/openspendingjs,openspending/openspendingjs,openspending/openspendingjs-old,openspending/openspendingjs-old