Don't capture file/line-numbers for COM objects in debug mode

.NET 4.7.1 has a major performance regression when capturing file and
line numbers in stack traces
(microsoft/dotnet#529) that was making debug
mode unusably slow so I'm turning that option off for now.

Viewer/src/viewer/VRApp.cs

@@ -15,7 +15,7 @@ public class VRApp : IDisposable {
 	private const bool debugDevice = false;
 
 	private static String GetStackTrace() {
-		return new StackTrace(4, true).ToString();
+		return new StackTrace(4, false).ToString();
 	}
 
 	[Conditional("DEBUG")]