[Change] Issue #12 调整框架启动机器人应用的方式, 增加一个用于机器人应用内部共享数据的类;

[Fix] BotEventHandler, ImageCacheStore 增加ShutdownHook用于关闭线程池, 解决线程池阻塞关闭过程的问题;
[Change] BotEventHandler 调整'match(String)'方法;
[Change] BotAdminCommandProcess 调整'savePushList()'方法对文件创建失败的行为;

src/main/java/net/lamgc/cgj/bot/cache/ImageCacheStore.java

@@ -33,6 +33,12 @@ public final class ImageCacheStore {
 
     private final static ImageCacheHandler handler = new ImageCacheHandler();
 
+    static {
+        Thread shutdownThread = new Thread(imageCacheExecutor::shutdownNow);
+        shutdownThread.setName("Thread-ImageCacheShutdown");
+        Runtime.getRuntime().addShutdownHook(shutdownThread);
+    }
+
     private ImageCacheStore() {}
 
     /**