dynamic import + bargenerator conflict.

[awb99]

dynamic import keeps an overview db, to ensure that the window that is locally in db has all the data between window-start and window-end.

dynamic import will only check for overview-db to trigger import-tasks.

ideas:

• bar-generator sets overview-db end-data, if the most recent added bar is exactly one bar after the last added bar in the overview-db.
• bar-generator is used like a bar-source. then the dynamic-import chain would be like
  1. compressor
  2. bargenerator-import
  3. feed-import