Add Summary to SpDay. Rails: create Summary, SummarySerializer, update SpDay, SpDaySerializer. Ember: Create HumonDaySummary; update SpDay metatemplates; update sp_day.emblem to include editor
Update Humon.templateContextFor: add documentation, modify default behavior to look up literal / hash template based on node
Switch Humon.HumonValue and Humon.Primitive name functions to use Ember.String.underscore