Prevent Dev title from showing up on Store builds (#627)

Commit 0722781fc updated the app to use `DevAppName` for the
app's window title when it was a non-official build, based on
the state of `IsStoreBuild`.

Unfortunately, `IsStoreBuild` is a _project_ level variable defined in
[build-app-internal.yaml](0722781fc6/build/pipelines/templates/build-app-internal.yaml (L36)),
but not a _compile-time_ defined value.

To solve this, we are now defining `IS_STORE_BUILD` in
`Calculator.vcxproj` when `IsStoreBuild='True'`, the same way that
we set `SEND_DIAGNOSTICS` for official builds, and we'll change the
window title based on that new `#define`.

Using this new `#define` can lead us down a slippery slope.  We need to
limit the amount of divergent code that we have between dev/official
builds.  This should be hopefully one of very few instances where
this value is ever used.

src/Calculator/Calculator.vcxproj

@@ -216,7 +216,7 @@
   </ItemDefinitionGroup>
   <ItemDefinitionGroup Condition="'$(IsStoreBuild)' == 'True'">
     <ClCompile>
-      <AdditionalOptions>/DSEND_DIAGNOSTICS %(AdditionalOptions)</AdditionalOptions>
+      <AdditionalOptions>/DSEND_DIAGNOSTICS /DIS_STORE_BUILD %(AdditionalOptions)</AdditionalOptions>
     </ClCompile>
   </ItemDefinitionGroup>
   <PropertyGroup>

src/Calculator/Views/TitleBar.xaml.cpp

@@ -36,11 +36,11 @@ namespace CalculatorApp
 
         Loaded += ref new RoutedEventHandler(this, &TitleBar::OnLoaded);
         Unloaded += ref new RoutedEventHandler(this, &TitleBar::OnUnloaded);
-#ifdef IsStoreBuild
+#ifdef IS_STORE_BUILD
         AppName->Text = AppResourceProvider::GetInstance().GetResourceString(L"AppName");
 #else
         AppName->Text = AppResourceProvider::GetInstance().GetResourceString(L"DevAppName");
-#endif //IsStoreBuild
+#endif //IS_STORE_BUILD
     }
 
     void TitleBar::OnLoaded(_In_ Object ^ /*sender*/, _In_ RoutedEventArgs ^ /*e*/)