Checklist for V1

[martindurant]

I am not sure whether we will indeed make a v1.0.0, calver or something else, but here is a wish-list of functionality.
This list may be updated.

• async mode for files (for backends that support it)
• file cache improvement for layout, expiry options and to store non-locally (RF idea: deprecate same_names in favor of a more generic layout parameter #555 caching location to be non-local #494)
• logging split into levels to allow better filtering, and added everywhere
• a set of directory operations tests across backends; here I am particularly thinking of the "directory" problem for object stores (Directories and delimiter handling #562)