Add a "Force re-download" button

[awebeer256]

Problem description
When a new version of a mod gets published on Steam, it doesn't always get downloaded right away.

Describe the solution
Add a button that deletes the current copy of the selected Steam mod and downloads a fresh copy. Also add a button to do this for all mods in the current modlist (with a warning).

It would be great if you could check whether the re-downloaded version is actually different, by checksums or something, and then flag the modlist as modified (requiring a game restart) if and only if it's different.

Alternatives
As far as I know, the best currently-existing way of achieving the same thing is to manually unsubscribe and resubscribe to the mod on Steam, possibly bracketed by removing and then re-adding it to the current modlist. This process involves many clicks and, I believe, at least two game restarts.