pointer-gestures: add a release request

This allows clients to destroy a gesture object before they disconnect.

The request isn't named "destroy", as this would conflict with
wayland-scanner's auto-generated destructor (which just destroys the
client-side object without sending any request).

Signed-off-by: Simon Ser <contact@emersion.fr>
Reviewed-by: Jonas Ådahl <jadahl@gmail.com>

unstable/pointer-gestures/pointer-gestures-unstable-v1.xml

@@ -1,7 +1,7 @@
 <?xml version="1.0" encoding="UTF-8"?>
 <protocol name="pointer_gestures_unstable_v1">
 
-  <interface name="zwp_pointer_gestures_v1" version="1">
+  <interface name="zwp_pointer_gestures_v1" version="2">
     <description summary="touchpad gestures">
       A global interface to provide semantic touchpad gestures for a given
       pointer.
@@ -37,9 +37,18 @@
       <arg name="id" type="new_id" interface="zwp_pointer_gesture_pinch_v1"/>
       <arg name="pointer" type="object" interface="wl_pointer"/>
     </request>
+
+    <!-- Version 2 additions -->
+
+    <request name="release" type="destructor" since="2">
+      <description summary="destroy the pointer gesture object">
+	Destroy the pointer gesture object. Swipe and pinch objects created via this
+	gesture object remain valid.
+      </description>
+    </request>
   </interface>
 
-  <interface name="zwp_pointer_gesture_swipe_v1" version="1">
+  <interface name="zwp_pointer_gesture_swipe_v1" version="2">
     <description summary="a swipe gesture object">
       A swipe gesture object notifies a client about a multi-finger swipe
       gesture detected on an indirect input device such as a touchpad.
@@ -102,7 +111,7 @@
     </event>
   </interface>
 
-  <interface name="zwp_pointer_gesture_pinch_v1" version="1">
+  <interface name="zwp_pointer_gesture_pinch_v1" version="2">
     <description summary="a pinch gesture object">
       A pinch gesture object notifies a client about a multi-finger pinch
       gesture detected on an indirect input device such as a touchpad.