App: Fix exception thrown when closing when yspath is invalid

Src/App/App.config

@@ -2,6 +2,6 @@
 <configuration>
   <appSettings>
     <clear />
-    <add key="YsPath" value="C:\dev\ysflight\20090502" />
+    <add key="YsPath" value="C:\dev\ysflight\20090611" />
   </appSettings>
 </configuration>

Src/App/YsfoWrapper.cs

@@ -69,13 +69,16 @@ public void Setup()
 
         public void Dispose()
         {
-            // save
-            LoadedAircraft.Save();
-            UnloadedAircraft.Save();
-            LoadedGround.Save();
-            UnloadedGround.Save();
-            LoadedScenery.Save();
-            UnloadedScenery.Save();
+            if (_ysfo.IsPathValid())
+            {
+                // save
+                if (LoadedAircraft != null) LoadedAircraft.Save();
+                if (UnloadedAircraft != null) UnloadedAircraft.Save();
+                if (LoadedGround != null) LoadedGround.Save();
+                if (UnloadedGround != null) UnloadedGround.Save();
+                if (LoadedScenery != null) LoadedScenery.Save();
+                if (UnloadedScenery != null) UnloadedScenery.Save();
+            }
 
             // cleanup
             _ysfo.Dispose();

Src/Core/Core.csproj

@@ -60,9 +60,6 @@
     <Compile Include="Properties\AssemblyInfo.cs" />
     <Compile Include="Ysfo.cs" />
   </ItemGroup>
-  <ItemGroup>
-    <None Include="app.config" />
-  </ItemGroup>
   <Import Project="$(MSBuildToolsPath)\Microsoft.CSharp.targets" />
   <!-- To modify your build process, add your task inside one of the targets below and uncomment it. 
        Other similar extension points exist, see Microsoft.Common.targets.

Ysfo.sln

@@ -21,7 +21,7 @@ Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Other", "Other", "{23108114
 EndProject
 Project("{54435603-DBB4-11D2-8724-00A0C9A8B90C}") = "Installer", "Other\Installer\Installer.vdproj", "{7A5C9E9E-5643-4E92-9DA2-01526DFF9BBE}"
 EndProject
-Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "License", "License", "{A3CD0C8F-E42A-4C51-91A6-BFEEBABDCE36}"
+Project("{2150E333-8FDC-42A3-9474-1A3956D46DE8}") = "Docs", "Docs", "{A3CD0C8F-E42A-4C51-91A6-BFEEBABDCE36}"
 	ProjectSection(SolutionItems) = preProject
 		LICENSE.markdown = LICENSE.markdown
 	EndProjectSection