Added meson buildfiles

this makes for a far better experience in combination with wlroots,
since that whole makefile mess is not required.
Additionaly, handling of wayland protocol sources is also slightly
better, but could be improved with mesons inbuilt wayland module.

To build Hyprland using meson:
    meson _build -Ddefault_library=static
    ninja -C _build
    ninja -C _build install

src/helpers/WLClasses.hpp

@@ -2,7 +2,7 @@
 
 #include "../events/Events.hpp"
 #include "../defines.hpp"
-#include "../../wlr-layer-shell-unstable-v1-protocol.h"
+#include "wlr-layer-shell-unstable-v1-protocol.h"
 #include "../Window.hpp"
 #include "SubsurfaceTree.hpp"
 #include "AnimatedVariable.hpp"
@@ -205,4 +205,4 @@ struct STabletPad {
     bool operator==(const STabletPad& b) {
         return wlrTabletPadV2 == b.wlrTabletPadV2;
     }
-};
+};