handled better errors and stack traces for more (all) cases

src/main/java/carpet/script/ScriptHost.java

@@ -1,6 +1,7 @@
 package carpet.script;
 
 import carpet.script.bundled.Module;
+import carpet.script.exception.ExpressionException;
 import carpet.script.exception.InternalExpressionException;
 import carpet.script.value.FunctionValue;
 import carpet.script.value.Value;
@@ -313,6 +314,12 @@ public abstract class ScriptHost
         return userHost;
     }
 
+    public void handleExpressionException(String msg, ExpressionException exc)
+    {
+        System.out.println(msg+": "+exc);
+    }
+
+
     protected abstract ScriptHost duplicate();
 
     public void onClose() { }