- Update to 1.4.1:
* ~/.mu -> ~/.cache/mu
* remove mentions of --rebuild
* properly close config group

-Update to 1.4:
mu:
* Defaults to XDG Base Directory Specification
* New subcommand `mu init` to initialize database -- takes
`--my-address` and `--maildir` parameters, `mu index` does not
accept them anymore
* New subcommand `mu info` to display information about the database
* Contacts are now saved in the database instead of in a separate
file
* `--xbatchsize` and `--autoupgrade` (for `mu index`) are removed,
both are implicit now
mu4e:
* Does not use `mu4e-maildir` and `mu4e-user-mail-address-list`
variables anymore, uses information from `mu init`
* Performance improvements related to contacts handling
* Added gnus' calendar-invitation handling
* Added support for custom headers
* Added experimental "Account Setup Handler"
* Org-mode support is enabled by default
* Speedbar support is disabled by default
* Messaged-id are added to draft messages (can be found with
`mu4e-headers-skip-duplicates` enabled)
* Bookmarks are simple plists now (`make-mu4e-bookmark` was updated)
* Specific bookmarks can be hidden from main menu
* `mu4e-maildir-shortcuts` are simple plists now (old format is still