Pivot notifications

pivot_fields: Foldr to change or add pivot fields for the main pivot table. The rsc contains all rsc properties for this resource, including pivot properties. Fold with a…
pivot_rsc_data: Fold over the resource props map to extend/remove data to be pivoted
pivot_update: Pivot just before a m_rsc_update update. Used to pivot fields before the pivot itself.
custom_pivot: Add custom pivot fields to a resource’s search index (map) Result is a single tuple or list of tuples {pivotname, props} , where “pivotname” is the pivot…