Fix warnings

src/Gui/DlgDisplayProperties.ui

@@ -377,10 +377,6 @@
     </layout>
    </item>
   </layout>
-  <zorder>groupBox2</zorder>
-  <zorder>groupBox3</zorder>
-  <zorder>groupBox1</zorder>
-  <zorder></zorder>
  </widget>
  <layoutdefault spacing="6" margin="11"/>
  <customwidgets>

src/Gui/DlgSettings3DView.ui

@@ -13,7 +13,7 @@
   <property name="windowTitle">
    <string>3D View</string>
   </property>
-  <layout class="QGridLayout">
+  <layout class="QGridLayout" name="gridLayout3">
    <property name="margin">
     <number>11</number>
    </property>
@@ -367,7 +367,7 @@
      <property name="title">
       <string>Camera type</string>
      </property>
-     <layout class="QGridLayout">
+     <layout class="QGridLayout" name="gridLayout1">
       <property name="margin">
        <number>11</number>
       </property>

src/Gui/DlgSettingsDocument.ui

@@ -19,7 +19,7 @@
      <property name="title">
       <string>General</string>
      </property>
-     <layout class="QGridLayout">
+     <layout class="QGridLayout" name="gridLayout_4">
       <property name="margin">
        <number>9</number>
       </property>

src/Mod/Mesh/App/Core/MeshIO.cpp

@@ -369,7 +369,7 @@ bool MeshInput::LoadSTL (std::istream &rstrIn)
     if (ulCt > 1)
         ulBytes = 100;
     // Either it's really an invalid STL file or it's just empty. In this case the number of facets must be 0.
-    if (rstrIn.read(szBuf, ulBytes) == false)
+    if (!rstrIn.read(szBuf, ulBytes))
         return (ulCt==0);
     szBuf[ulBytes] = 0;
     upper(szBuf);

src/Mod/Part/Gui/DlgSettingsGeneral.ui

@@ -19,7 +19,7 @@
      <property name="title">
       <string>Export</string>
      </property>
-     <layout class="QGridLayout">
+     <layout class="QGridLayout" name="gridLayout_1">
       <property name="margin">
        <number>9</number>
       </property>