d_a_alink work / lv4digsand done / e_s1 matched (#2224)

* d_a_alink work / d_a_obj_lv4digsand done

* d_a_e_s1 matched, not linked

* d_a_e_s1 documentation

include/m_Do/m_Do_ext.h

@@ -420,6 +420,7 @@ public:
     u16 getOldFrameStartJoint() { return mOldFrameStartJoint; }
     u16 getOldFrameEndJoint() { return mOldFrameEndJoint; }
     Quaternion* getOldFrameQuaternion(int i_no) { return &mOldFrameQuaternion[i_no]; }
+    f32 getOldFrameMorfCounter() { return mOldFrameMorfCounter; }
 
 private:
     /* 0x00 */ bool mOldFrameFlg;