完善 @TCommand 注解

新增 TCommandHandler 类用于动态命令注册

src/main/java/com/ilummc/tlib/util/Ref.java

@@ -12,6 +12,7 @@ import sun.reflect.Reflection;
 
 import javax.annotation.concurrent.ThreadSafe;
 import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
 import java.util.*;
 import java.util.concurrent.ConcurrentHashMap;
 import java.util.stream.Collectors;