Use linearInterpolator as default interpolator for command animations

lib/android/app/src/main/java/com/reactnativenavigation/parse/params/Interpolation.java

 import android.view.animation.AccelerateDecelerateInterpolator;
 import android.view.animation.AccelerateInterpolator;
 import android.view.animation.DecelerateInterpolator;
+import android.view.animation.LinearInterpolator;
 
 public enum Interpolation {
-    ACCELERATING,
-    DECELERATING,
+    ACCELERATE,
+    DECELERATE,
+    ACCELERATE_DECELERATE,
     DEFAULT,
     NO_VALUE;
 
     public TimeInterpolator getInterpolator() {
         switch (this) {
-            case ACCELERATING:
+            case ACCELERATE:
                 return new AccelerateInterpolator();
-            case DECELERATING:
+            case DECELERATE:
                 return new DecelerateInterpolator();
-            case DEFAULT:
+            case ACCELERATE_DECELERATE:
                 return new AccelerateDecelerateInterpolator();
+            case DEFAULT:
+                return new LinearInterpolator();
         }
         return null;
     }

lib/android/app/src/main/java/com/reactnativenavigation/parse/parsers/InterpolationParser.java

 
 public class InterpolationParser {
     public static Interpolation parse(JSONObject json, String interpolation) {
-        Interpolation result = Interpolation.DEFAULT;
-        if (json.has(interpolation)) {
-            switch (json.optString(interpolation)) {
-                case "decelerate":
-                    result = Interpolation.DECELERATING;
-                    break;
-                case "accelerate":
-                    result = Interpolation.ACCELERATING;
-                    break;
-            }
+        switch (json.optString(interpolation, "default")) {
+            case "decelerate":
+                return Interpolation.DECELERATE;
+            case "accelerateDecelerate":
+                return Interpolation.ACCELERATE_DECELERATE;
+            case "accelerate":
+                return Interpolation.ACCELERATE;
+            default:
+                return Interpolation.DEFAULT;
         }
-        return result;
     }
 }