Comment 4 for bug 1335810

Done last CMS comment.

Will assign to Alex for Python client alterations.

Required Files contains a new field called "updated" which is the unixtime stamp that resource was last updated on the server. When deciding whether to download the file the client should look at that stamp and compare it to the last write time on the file.

If the last write time is before the stamp, then download the file.

This means data sets update without them being the in the schedule (they just need to be within required files).