Schematic list deny negative numbers

Signed-off-by: Lixfel <agga-games@gmx.de>

SchematicSystem_Main/src/de/steamwar/schematicsystem/commands/SchematicCommand.java

@@ -475,7 +475,7 @@ public class SchematicCommand implements CommandExecutor {
         }else
             pages = intPages;
 
-        if(currentPage >= pages) return;
+        if(currentPage >= pages || currentPage < 0) return;
 
         player.sendMessage("§eSeite " + (currentPage + 1) + " §8/ " + pages + " §8| §e" + schematicList.size() + " Schematics");