Create a custom macro akin to G_DEFINE_TYPE() in order to generate the
boilerplate.

Replace manual get_type() implementations with G_DEFINE_TYPE() macros.

Add accessible implementation for EelLabeledImageButton,
EelLabeledImageCheckButton, EelLabeledImageToggleButton and
EelLabeledImageRadioButton.

The implementation is actually the same as the one for EelLabeledImage
which already handles the button cases, this just plugs in the right
bits for those other types to use it properly.

This fixes accessibility of the emblem selector in the file properties
window as well as the groups in the "property borwser" (the
"Backgrounds & Emblems" window).

Do not manually store the parent class which is already available thanks
to G_DEFINE_TYPE().

*Draw the background on the desktop window, using the same code as on navigation windows to bypass the no-root-window issue.
*Works from caja's "Change Desktop Background" menu item, from caja-extensions "set as wallpaper" and with changing the background in dconf-editor.
*All background options available in x11 supported in wayland, UI is new for wayland

*Apply changes immediately, keep the dialog open until closed by user
*Let users see changes in realtime while keeping the dialog open
*Preview both colors and pictures
*Add ability to apply changes from either combobox including using any image saved from when dialog was opened
*Add tooltips to the buttons, filepicker, and comboboxes

* Wayland: Support rendering the desktop

*Wayland support is optional via the --enable-wayland option

* eel-editable-label-c: remove unused variable

This was leftover from earlier code compatable only with x11

* Fix gtk-layer-shell-0 version check, improve error message when Wayland requested but not found