media-player: Move navigation buttons into a box

This makes {first,last}-child styling way simpler
Signed-off-by: Guido Günther <guido.gunther@puri.sm>

src/ui/media-player.ui

@@ -10,59 +10,57 @@
     <property name="margin_bottom">5</property>
     <property name="column_homogeneous">True</property>
     <child>
-      <object class="GtkButton" id="btn_prev">
+      <object class="GtkBox">
         <property name="visible">True</property>
-        <property name="can_focus">True</property>
-        <property name="receives_default">True</property>
-        <signal name="clicked" handler="btn_prev_clicked_cb" object="PhoshMediaPlayer" swapped="yes"/>
+        <property name="homogeneous">True</property>
         <child>
-          <object class="GtkImage">
+          <object class="GtkButton" id="btn_prev">
             <property name="visible">True</property>
-            <property name="can_focus">False</property>
-            <property name="icon_name">media-skip-backward-symbolic</property>
+            <property name="can_focus">True</property>
+            <property name="receives_default">True</property>
+            <signal name="clicked" handler="btn_prev_clicked_cb" object="PhoshMediaPlayer" swapped="yes"/>
+            <child>
+              <object class="GtkImage">
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+                <property name="icon_name">media-skip-backward-symbolic</property>
+              </object>
+            </child>
           </object>
         </child>
-      </object>
-      <packing>
-        <property name="left_attach">0</property>
-        <property name="top_attach">1</property>
-      </packing>
-    </child>
-    <child>
-      <object class="GtkButton" id="btn_play">
-        <property name="visible">True</property>
-        <property name="can_focus">True</property>
-        <property name="receives_default">True</property>
-        <signal name="clicked" handler="btn_play_clicked_cb" object="PhoshMediaPlayer" swapped="yes"/>
         <child>
-          <object class="GtkImage" id="img_play">
+          <object class="GtkButton" id="btn_play">
             <property name="visible">True</property>
-            <property name="can_focus">False</property>
-            <property name="icon_name">media-playback-start-symbolic</property>
+            <property name="can_focus">True</property>
+            <property name="receives_default">True</property>
+            <signal name="clicked" handler="btn_play_clicked_cb" object="PhoshMediaPlayer" swapped="yes"/>
+            <child>
+              <object class="GtkImage" id="img_play">
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+                <property name="icon_name">media-playback-start-symbolic</property>
+              </object>
+            </child>
           </object>
         </child>
-      </object>
-      <packing>
-        <property name="left_attach">1</property>
-        <property name="top_attach">1</property>
-      </packing>
-    </child>
-    <child>
-      <object class="GtkButton" id="btn_next">
-        <property name="visible">True</property>
-        <property name="can_focus">True</property>
-        <property name="receives_default">True</property>
-        <signal name="clicked" handler="btn_next_clicked_cb" object="PhoshMediaPlayer" swapped="yes"/>
         <child>
-          <object class="GtkImage">
+          <object class="GtkButton" id="btn_next">
             <property name="visible">True</property>
-            <property name="can_focus">False</property>
-            <property name="icon_name">media-skip-forward-symbolic</property>
+            <property name="can_focus">True</property>
+            <property name="receives_default">True</property>
+            <signal name="clicked" handler="btn_next_clicked_cb" object="PhoshMediaPlayer" swapped="yes"/>
+            <child>
+              <object class="GtkImage">
+                <property name="visible">True</property>
+                <property name="can_focus">False</property>
+                <property name="icon_name">media-skip-forward-symbolic</property>
+              </object>
+            </child>
           </object>
         </child>
       </object>
       <packing>
-        <property name="left_attach">2</property>
+        <property name="left_attach">0</property>
         <property name="top_attach">1</property>
       </packing>
     </child>
@@ -148,7 +146,6 @@
       <packing>
         <property name="left_attach">0</property>
         <property name="top_attach">0</property>
-        <property name="width">3</property>
       </packing>
     </child>
   </template>