Increase double-click distance tolerance (MR 10)

This makes double-clicking on touchscreens easier where needed.
It shouldn't hurt laptop usage too much.

config/xfce4/xfconf/xfce-perchannel-xml/xsettings.xml

@@ -3,5 +3,6 @@
 <channel name="xsettings" version="1.0">
   <property name="Net" type="empty">
     <property name="IconThemeName" type="string" value="Faenza-Ambiance"/>
+    <property name="DoubleClickDistance" type="int" value="20"/>
   </property>
 </channel>