The isExported option should only apply to files

tests/reference/gui/1_nwProject.nwx

@@ -1,5 +1,5 @@
 <?xml version='1.0' encoding='utf-8'?>
-<novelWriterXML appVersion="0.5" fileVersion="1.0" saveCount="4" autoCount="0" timeStamp="2020-05-10 19:34:57">
+<novelWriterXML appVersion="0.5" fileVersion="1.0" saveCount="4" autoCount="0" timeStamp="2020-05-10 23:18:06">
   <project>
     <name></name>
     <title></title>
@@ -42,7 +42,6 @@
       <class>NOVEL</class>
       <status>New</status>
       <expanded>True</expanded>
-      <exported>True</exported>
     </item>
     <item handle="25fc0e7096fc6" order="0" parent="73475cb40a568">
       <name>New Chapter</name>
@@ -50,7 +49,6 @@
       <class>NOVEL</class>
       <status>New</status>
       <expanded>True</expanded>
-      <exported>True</exported>
     </item>
     <item handle="31489056e0916" order="0" parent="25fc0e7096fc6">
       <name>New Scene</name>
@@ -71,7 +69,6 @@
       <class>CHARACTER</class>
       <status>New</status>
       <expanded>True</expanded>
-      <exported>True</exported>
     </item>
     <item handle="98010bd9270f9" order="0" parent="44cb730c42048">
       <name>New File</name>
@@ -92,7 +89,6 @@
       <class>PLOT</class>
       <status>New</status>
       <expanded>True</expanded>
-      <exported>True</exported>
     </item>
     <item handle="0e17daca5f3e1" order="0" parent="71ee45a3c0db9">
       <name>New File</name>
@@ -113,7 +109,6 @@
       <class>WORLD</class>
       <status>New</status>
       <expanded>True</expanded>
-      <exported>True</exported>
     </item>
     <item handle="1a6562590ef19" order="0" parent="811786ad1ae74">
       <name>New File</name>