Center, switch and change text for confirmation buttons

The confirmation buttons for quitting or starting a new game were
driving me crazy by not being ok left and cancel right, as e.g. vanilla
is.

Then I noticed the text isn't the same as in vanilla either. It should
be yes/no, not ok/cancel.

To make it even more authentic I also centered the buttons. Had to
remove autosized buttons for this. I think it looks fine still.

Comments?

files/mygui/openmw_confirmation_dialog.layout

@@ -4,7 +4,7 @@
     <Widget type="Window" skin="MW_Dialog" layer="Windows" position="0 0 300 130" name="_Main">
         <Property key="Visible" value="false"/>
 
-        <Widget type="EditBox" skin="MW_TextEditClient" position="8 8 284 400" name="Message" align="Left Top Stretch">
+        <Widget type="EditBox" skin="MW_TextEditClient" position="8 8 274 400" name="Message" align="Left Top Stretch">
             <Property key="FontName" value="Default"/>
             <Property key="TextAlign" value="Top HCenter"/>
             <Property key="TextColour" value="0.75 0.6 0.35"/>
@@ -13,18 +13,13 @@
             <Property key="MultiLine" value="true"/>
         </Widget>
 
-        <Widget type="HBox" position="0 89 284 24" align="Right Bottom">
-            <Widget type="Widget">
-                <UserString key="HStretch" value="true"/>
+        <Widget type="Widget" position="0 89 274 24" align="Center Bottom">
+            <Widget type="Button" skin="MW_Button" name="OkButton" position="77 0 60 24">
+                <Property key="Caption" value="#{sYes}"/>
             </Widget>
-            <Widget type="AutoSizedButton" skin="MW_Button" name="CancelButton" align="Right Bottom">
-                <Property key="Caption" value="#{sCancel}"/>
-            </Widget>
-            <Widget type="AutoSizedButton" skin="MW_Button" name="OkButton" align="Right Bottom">
-                <Property key="Caption" value="#{sOk}"/>
+            <Widget type="Button" skin="MW_Button" name="CancelButton" position="147 0 60 24">
+                <Property key="Caption" value="#{sNo}"/>
             </Widget>
         </Widget>
-
     </Widget>
-</MyGUI>
-
+</MyGUI>