Addresses #319

• Support for multiple outputs, configuable through wlr-output-management-unstable-v1 protocol (eg. wlr-randr, wdisplays).
• Root menu can be generated from XDG repository (#90, eg. wmmenugen), and can be navigated by keyboard.
• User manual at https://phkaeser.github.io/wlmaker/.
• Bug fix: wlmclock now keeps updating also on on-accelerated garphics backends.

• Adds window menu, and enables it for xdg_toplevel.
• Adds root menu, configurable via a plist text file.
• Fixes #158 and adds rudimentary support for wlr-layer-shell-unstable-v1 keyboard interactivity.

Addressing #133

• New feature: Options for specifying layout and scaling factor for the output.
• New feature: Hot corner -- configurable actions when moving pointer to a corner, eg. to lock screen or inhibit locking.
• Fix: Scales tiles, icons and window decorations sizes as configured, not just for 64x64 tiles.
• Fix: Various bugs that prevented proper keyboard and pointer focus after unlocking the screen.
• Build system updates: Permit building with wlroots-0.18, and permit building from pre-packaged wlroots 0.17.

• Adds screen saver support, through ext_session_lock_v1 and idle_inhibit_unstable_v1 protocols.
• Configurable through plist text files: base configuration, style and etc/wlmaker-state.plist.
• Full wlr layer shell support (wlr_layer_shell_unstable_v1), fully implemented & tested.

• Major architecture rework, now handles asynchronous commit/request sequences (size, fullscreen, maximize) correctly.
• Adds initial support for X11 via xwayland.
• Adds a prototype implementation of an icon protocol, and a DockApp to verify.