wayland: implement pointer-gestures-unstable-v1

wire/zwp_pointer_gesture_pinch_v1.txt

@@ -0,0 +1,24 @@
+request destroy {
+
+}
+
+event begin {
+    serial: u32,
+    time: u32,
+    surface: id(wl_surface),
+    fingers: u32,
+}
+
+event update {
+    time: u32,
+    dx: fixed,
+    dy: fixed,
+    scale: fixed,
+    rotation: fixed,
+}
+
+event end {
+    serial: u32,
+    time: u32,
+    cancelled: i32,
+}