Add FROG_RUNNER_MODE environment variable for debugging

src/main/java/at/compax/tools/sql/main/Main.java

@@ -128,6 +128,13 @@ public class Main {
   }
 
   public static void main(String[] args) throws Exception {
+    String frogRunnerMode = System.getenv("FROG_RUNNER_MODE");
+    if (frogRunnerMode != null) {
+      if (frogRunnerMode.equals("TERMINAL")) {
+        executionMode = ExecutionMode.TERMINAL;
+      }
+    }
+
     BasicConfigurator.configure();
     LogManager.getRootLogger().setLevel(Level.OFF);
     LogManager.getLogger("at.compax.tools.sql.main").setLevel(executionMode.getLoggingLevel());