Add another example application

This new step sets the headerbar as titlebar, and enables
fallback for the app menu.

examples/application10/org.gtk.exampleapp.gschema.xml

@@ -0,0 +1,25 @@
+<?xml version="1.0" encoding="UTF-8"?>
+<schemalist>
+  <schema path="/org/gtk/exampleapp/" id="org.gtk.exampleapp">
+    <key name="font" type="s">
+      <default>'Monospace 12'</default>
+      <summary>Font</summary>
+      <description>The font to be used for content.</description>
+    </key>
+    <key name="transition" type="s">
+      <choices>
+        <choice value='none'/>
+        <choice value='crossfade'/>
+        <choice value='slide-left-right'/>
+      </choices>
+      <default>'none'</default>
+      <summary>Transition</summary>
+      <description>The transition to use when switching tabs.</description>
+    </key>
+    <key name="show-words" type="b">
+      <default>false</default>
+      <summary>Show words</summary>
+      <description>Whether to show a word list in the sidebar</description>
+    </key>
+  </schema>
+</schemalist>