The "Post-Deterrence Era" release

Now that the recent Textual breaking changes period seems to have calmed down a wee bit, I'm daring to unpin the library. This release also includes a couple of fixes for breaking changes that were introduced, and also tries to make some sense of (and work around) some curious cosmetic choices made for the Footer widget.

In terms of how Tinboard itself works, everything should be the same, albeit with the odd cosmetic change here and there.