Code refactoring to fix some lint warnings

Author: hannesa2

MPChartLib/src/main/java/com/github/mikephil/charting/components/AxisBase.java

@@ -603,7 +603,7 @@ public void disableGridDashedLine() {
      * @return
      */
     public boolean isGridDashedLineEnabled() {
-        return mGridDashPathEffect == null ? false : true;
+        return mGridDashPathEffect != null;
     }
 
     /**
@@ -655,7 +655,7 @@ public void disableAxisLineDashedLine() {
      * @return
      */
     public boolean isAxisLineDashedLineEnabled() {
-        return mAxisLineDashPathEffect == null ? false : true;
+        return mAxisLineDashPathEffect != null;
     }
 
     /**

MPChartLib/src/main/java/com/github/mikephil/charting/data/BaseDataSet.java

@@ -92,8 +92,8 @@ public abstract class BaseDataSet<T extends Entry> implements IDataSet<T> {
      * Default constructor.
      */
     public BaseDataSet() {
-        mColors = new ArrayList<Integer>();
-        mValueColors = new ArrayList<Integer>();
+        mColors = new ArrayList<>();
+        mValueColors = new ArrayList<>();
 
         // default color
         mColors.add(Color.rgb(140, 234, 255));
@@ -201,7 +201,7 @@ public void setColors(int[] colors, Context c) {
      */
     public void addColor(int color) {
         if (mColors == null)
-            mColors = new ArrayList<Integer>();
+            mColors = new ArrayList<>();
         mColors.add(color);
     }
 
@@ -244,7 +244,7 @@ public void setColors(int[] colors, int alpha) {
      */
     public void resetColors() {
         if (mColors == null) {
-            mColors = new ArrayList<Integer>();
+            mColors = new ArrayList<>();
         }
         mColors.clear();
     }

MPChartLib/src/main/java/com/github/mikephil/charting/renderer/PieChartRenderer.java

@@ -1055,7 +1055,7 @@ protected void drawRoundedSlices(Canvas c) {
     }
 
     /**
-     * Releases the drawing bitmap. This should be called when {@link LineChart#onDetachedFromWindow()}.
+     * Releases the drawing bitmap. This should be called when .
      */
     public void releaseBitmap() {
         if (mBitmapCanvas != null) {