Delete lingering MyEasingFunction.java

I made the decision to remove this file instead of updating it, as I'm
sure most will instead prefer to look at the actual Easing class. If you
miss this example class... ¯\_(ツ)_/¯

MPChartExample/src/com/xxmassdeveloper/mpchartexample/custom/MyEasingFunction.java

@@ -1,18 +0,0 @@
-
-package com.xxmassdeveloper.mpchartexample.custom;
-
-import com.github.mikephil.charting.animation.EasingFunction;
-
-/**
- * Example of a custom made animation EasingFunction.
- * 
- * @author Philipp Jahoda
- */
-public class MyEasingFunction implements EasingFunction {
-
-    @Override
-    public float getInterpolation(float input) {
-        // do awesome stuff here, this is just linear easing
-        return input;
-    }
-}