Only detects features from previous version when a bundle is found.
Otherwise, stray registry entries would cause issues.
Also fixes an accelerator collision and improves UAC icons when upgrading.
diff --git a/Tools/msi/bundle/Default.wxl b/Tools/msi/bundle/Default.wxl
index 235f6e4..1f3e77c 100644
--- a/Tools/msi/bundle/Default.wxl
+++ b/Tools/msi/bundle/Default.wxl
@@ -52,7 +52,7 @@
   <String Id="InstallSimpleButtonNote">Use settings preselected by your administrator
 
 [SimpleInstallDescription]</String>
-  <String Id="InstallUpgradeButton">&amp;Upgrade Now</String>
+  <String Id="InstallUpgradeButton">Up&amp;grade Now</String>
   <String Id="InstallUpgradeButtonNote">[TargetDir]
 
 Replaces your existing installation without changing settings.