start doc work phase 2.
linking adjustments
finish doc 'Advanced Linking'.
Outline for remaining docs
Add ring support doc
Remove LinkFromBlock() to clarify API.
Add CircularFlow demo
finish ring support part
doc on StatisticsRecorder
Add PeopleFlow, the demo for StatisticsRecorder
Add recorder demo code in doc
Add bulk insertion doc and demo (not finished yet)
fix bulk inserter demo
continue bulk insertion support
More doc on DbBulkInserter
Add second dbbulkinserter demo
add missing file
make sure dataflow is cleaned up even if there is exception from child
Add pictures
fix picture showing