Increase `undo-limit`, `undo-strong-limit` and `undo-outer-limit` by a
factor of ten, which should prevent emacs from prematurely truncating
the undo history and corrupting the tree.
Restore `undo-tree-auto-save-history` which was disabled to avoid
exacerbating the undo history truncation.
Change the `undo-tree` recipe to grab the latest version from the
maintainer's repostiory instead of the outdated ELPA version.
Restore `undo-tree-enable-undo-in-region` which should be fixed in the
latest version of `undo-tree`.
aa087e3af2