Add s_last3hourTimeRange to dashboard controller and dashboard.emblem
Add DashboardController#dayStart, defaults to 9:30. Add s_sinceDayStart time range string. Update dashboard.emblem to show time ranges in productivity summary
Add nextNode logic to NodeView#deletePressed; calls smartFocus on nextNode.nodeView
Simplify layout on data point.emblem: remove endedAt; removed usmbittedAt; renamed Started At to At
Update debugger panel to have constant line heights
Add Util.mixpanel
 Add initializers/active_model_serializer_override.rb to set as_json on DefaultSerializer