Summary:
Add of new proof/file with same specs should optionally overwrite
Detailed Description:
When we send a proof, but the client takes no action, if we send a new file
with the same specs, it adds it to the job. Would it be difficult to make it
so if the job number and job name match, it would replace the existing one
rather than add to it? (the physical file name might be different, as we use
_rev1 etc) but the name we actually type in when sending the proof would be
the indicator.