Add global minor modes for EXWM's features

[Stebalien]

(fixup commits before merging)

[Stebalien]

This applies the feedback from #43.

Unfortunately, the autoloads aren't quite correct for minor modes and I'm not sure if there's a way to fix them while still using macros. Specifically, the autoloads should look something like:

(defvar exwm-systemtray-mode nil "....")
(custom-autoload exwm-systemtray-mode "exwm-systemtray" nil)
(autoload 'exwm-systemtray-mode "exwm-systemtray" "..." t)

Importantly, we're missing the custom-autoload which lets one enable minor-modes via the customize system.

[minad]

Unfortunately, the autoloads aren't quite correct for minor modes and I'm not sure if there's a way to fix them while still using macros. Specifically, the autoloads should look something like:

Maybe a better alternative would be to not use a macro for the whole mode, but only for the body exwm--minor-mode-body? It could also be a function taking a symbol argument. We cannot automatically define the obsolete function then, but we side step the autoload problem.

[progfolio]

This applies the feedback from #43.

Unfortunately, the autoloads aren't quite correct for minor modes and I'm not sure if there's a way to fix them while still using macros. Specifically, the autoloads should look something like:

(defvar exwm-systemtray-mode nil "....")
(custom-autoload exwm-systemtray-mode "exwm-systemtray" nil)
(autoload 'exwm-systemtray-mode "exwm-systemtray" "..." t)

Importantly, we're missing the custom-autoload which lets one enable minor-modes via the customize system.

Anything after the autoload-cookie will be copied verbatim to the generated autoloads file.
e.g.

;;;###autoload(defvar exwm-xsettings-mode nil)
;;;###autoload(custom-autoload 'exwm-xsettings-mode "exwm-xsettings" nil)
;;;###autoload(autoload 'exwm-xsettings-mode "exwm-xsettings"
;;;###autoload"Global minor mode for toggling EXWM Xsettings support.")
(exwm--define-global-minor-mode xsettings
  "Global minor mode for toggling EXWM Xsettings support.")

[progfolio]

@Stebalien see #46

[minad]

Merged #46