Implement a checksum + cache mechanism to check whether user is sending the same file multiple times:this is needed to address the problem of timeouts, where the server might process a request even when the client has given up and rescheduled the upload. We now store the latest checksum that has been received and compare it with the new picture.
Make sure that the context_id of a CRItem is always fetched from that of the item, rather than the revision, otherwise we could break object_id = context_id constraint on saving
moved answer status into answer_panel (similar to downstream),made sensitivity of inspect links automatically updating (like downstream)made templating easier and refactored code
