Taskbar functionality on wayland with foreign-toplevel protocol

[dkondor]

See https://github.com/swaywm/wlr-protocols/blob/master/unstable/wlr-foreign-toplevel-management-unstable-v1.xml This protocol provides for a wayland client to manage other windows, so it can be used to implement a taskbar. It is supported on wlroots-based compositors.

Basic actions work:

• adding / removing icons when windows open / close
• matching to launchers
• activate, minimize, close actions

Not working:

• changing workspaces / figuring out which workspace a window is on
• getting the position / size of windows (not supported in this protocol); all windows are assumed to be in the top left corner, this can confuse the dock if "Hide the dock when it overlaps with windows" is selected.
• subdocks show up as icons
• minimize to icon (supported by the protocol, but I haven't implemented it yet)

Tested on Wayfire https://github.com/WayfireWM/wayfire/ For best results, needs the layer-shell functionality as well (https://github.com/Cairo-Dock/cairo-dock-core/pull/8), otherwise it is weird to focus the dock.

Other issues:

• protocol files (wlr-foreign-toplevel-*) should not be added as source files, but generated at build time from the xml protocol definition

[dkondor]

Closing in favor of #15