Load each category of a source whose manifest carries an index on first reach, and move the shipped index into data/.fejkdata.json

node.go

@@ -22,7 +22,7 @@ type node interface{ isNode() }
 // dot path; rendering one is an error (see Fake).
 type folder struct {
 	children map[string]node
-	unloaded map[string]shippedEntry // the shipped categories here a call has not reached yet
+	unloaded map[string]indexed // the categories here an index names and no call has reached yet
 }
 
 func (*folder) isNode() {}