Cachers that specify path_overrides don't track

[WarmCyan]

This is due to the difficulty in doing the path translation to the store full path. This is (unfortunately) going to plague #113

This is partially because the path translation assumes always strictly having the subdir/prefix/name etc, and we get none of those esp if it's an inline cacher or similar.

We should probably note that using the string templating in cachers is pretty specifically only for things like raw data processing that we never want per-parameter set, or will effectively never want in a full store anyway