Fix the problem that the pool static property holds the View referenc…

MPChartLib/src/main/java/com/github/mikephil/charting/jobs/AnimatedMoveViewJob.java

@@ -36,6 +36,7 @@ public static AnimatedMoveViewJob getInstance(ViewPortHandler viewPortHandler, f
     }
 
     public static void recycleInstance(AnimatedMoveViewJob instance){
+        instance.recycle();
         pool.recycle(instance);
     }
 

MPChartLib/src/main/java/com/github/mikephil/charting/jobs/MoveViewJob.java

@@ -30,6 +30,7 @@ public static MoveViewJob getInstance(ViewPortHandler viewPortHandler, float xVa
     }
 
     public static void recycleInstance(MoveViewJob instance){
+        instance.recycle();
         pool.recycle(instance);
     }
 

MPChartLib/src/main/java/com/github/mikephil/charting/jobs/ViewPortJob.java

@@ -44,4 +44,10 @@ public float getXValue() {
     public float getYValue() {
         return yValue;
     }
+
+    public void recycle() {
+        mViewPortHandler = null;
+        mTrans = null;
+        view = null;
+    }
 }

MPChartLib/src/main/java/com/github/mikephil/charting/jobs/ZoomJob.java

@@ -37,6 +37,7 @@ public static ZoomJob getInstance(ViewPortHandler viewPortHandler, float scaleX,
     }
 
     public static void recycleInstance(ZoomJob instance) {
+        instance.recycle();
         pool.recycle(instance);
     }