Ordering of Promises

ServiceOptimizer does not order the list of Time Bands returned. More specifically, Time Bands are grouped together by band type, and a cost function is applied to order the Promises within a single band type; this is known as ranking. However, if there are several groups each of a different band type, they are returned in arbitrary order. If it is required to order the band type groups (e.g. to have all day Time Bands first) this must be done by the booking client. To facilitate this, ServiceOptimizer returns the band type with each Promise.