skip janitor if planPIndexes is nil
comments and var rename
downstream structs now are superset of upstream structs
changed type of indexMapping to string
note on ImplVersion during CreateIndex()
more simple planner
CalcPIndexesDelta() is closer to real
CalcPIndexesDelta() now only focuses on the subset of plan for the local node
need to teardown wrong feeds/pindexes before doing additions
each Feed has Streams map to support fan-out
reimplement api DeleteIndex to use cfg and planner kicking
panic rather than have undefined state in StopPIndex()
implemented StartPIndex()