Tweak default toolbar to fit View Mode combobox

This is a useful UI element that I find myself using a lot, so quick
access is helpful. Another person just submitted a similar change (see
!689) so it would seem there is some demand for this.

In its current form, the toolbar contents would be too long if we added
it, and items would get pushed into the overflow menu. To prevent this,
let's also drop the separator lines and text from the zoom buttons.

part/part.rc

@@ -1,6 +1,6 @@
 <?xml version="1.0"?>
 <!DOCTYPE gui SYSTEM "kpartgui.dtd">
-<gui name="okular_part" version="52">
+<gui name="okular_part" version="53">
 <MenuBar>
   <Menu name="file"><text>&amp;File</text>
     <Action name="get_new_stuff" group="file_open"/>
@@ -100,7 +100,6 @@
 </MenuBar>
 <ToolBar name="mainToolBar"><text>Main Toolbar</text>
   <Action name="show_leftpanel"/>
-  <Separator/>
   <Action name="mouse_drag"/>
   <Action name="mouse_selecttools"/>
   <Action name="annotation_favorites"/>
@@ -110,11 +109,13 @@
   <Action name="view_zoom_out"/>
   <Action name="zoom_to" />
   <Action name="view_zoom_in"/>
-  <Separator/>
+  <Action name="view_render_mode"/>
   <Action name="hamburger_menu"/>
 </ToolBar>
 <ActionProperties scheme="Default">
   <Action priority="0" name="show_leftpanel"/>
+  <Action priority="0" name="view_zoom_out"/>
+  <Action priority="0" name="view_zoom_in"/>
 </ActionProperties>
 <ToolBar name="annotationToolBar" iconText="icononly" newline="true" hidden="true"><text>Annotation Toolbar</text>
   <Action name="annotation_highlighter"/>