added push-pull train condition

src/main/java/de/srsoftware/web4rail/conditions/PushPullTrain.java

@@ -0,0 +1,16 @@
+package de.srsoftware.web4rail.conditions;
+
+import de.srsoftware.web4rail.actions.Action.Context;
+
+public class PushPullTrain extends Condition {
+	
+	@Override
+	public boolean fulfilledBy(Context context) {
+		return context.train.pushPull != inverted;
+	}
+
+	@Override
+	public String toString() {
+		return t(inverted ? "train is not a push-pull train":"train is a push-pull train") ;
+	}
+}