- remove unused import.
- change SimpleItem.py to use python logging module
- log at error when standard_error_message can't be rendered
- give more useful info about errors rendering standard_error_message to the browser.
- all conflict errors are counted and logged at info
- logging makes it clear where the conflict has been resolved and where it hasn't
- errors seen by the user are rendered with standard_error_message and are sent to the error_log which will likely copy them to the event log, depending on the users setup.
- also checking in a functional test for generating write conflict errors.
  
(I'll be committing to CHANGES.TXT shortly, I just wanted to keep the merges simpler)