Lowercase all subdirectories of ~/
zsh: less quoting
aurget: use /tmp, test eager sudo
vim: remove custom backup directory

Using /tmp means that we can't recover from a crash that causes a
restart (since /tmp is cleared). This customization was from a time when
swap files weren't correctly git-ignored. Now that they are, the default
(alongside the actual file) is fine.
vim: use -Wall in ghci mapping