handle files with no statements

Program.cs

@@ -135,6 +135,11 @@ namespace BunyMuny {
 				Console.WriteLine(statement);
 			}
 
+			if (statements.Count == 0) {
+				Console.WriteLine("No statements found.");
+				return 2;
+			}
+
 			Console.WriteLine("Summary:");
 			Console.WriteLine("==================");
 			var summaries = statements.GroupBy(s => s.Category). // group statements by category