整理代码，添加部分注释

others/include/constants.h

@@ -0,0 +1,17 @@
+//
+// Created by xinyang on 19-7-8.
+//
+
+#ifndef _CONSTANTS_H_
+#define _CONSTANTS_H_
+
+#define PI (3.14159265459)
+
+#define ENEMY_BLUE 0
+#define ENEMY_RED  1
+
+#define BIG_ENERGY_STATE   'b'
+#define SMALL_ENERGY_STATE 's'
+#define ARMOR_STATE        'a'
+
+#endif /* _CONSTANTS_H */