Add the ability to "rollup" values in a time series (#554)

* Clean up time series models

* Add value group rollup class for summarizing hierarchical data

* Integrate new classes

* Update UI to use new patterns

* Update D3 charts to expect new data format

* Clean up account model

* More cleanup

* Money improvements

* Use new money fields

* Remove invalid fixture data to avoid orphaned accountables

* Update time series to work better with collections

* Fix tests and UI bugs

app/helpers/application_helper.rb

@@ -29,6 +29,7 @@ module ApplicationHelper
 
 
 
+
   def sidebar_modal(&block)
     content = capture &block
     render partial: "shared/sidebar_modal", locals: { content: content }