Support showing modals without animation (#900)

android/app/src/main/java/com/reactnativenavigation/controllers/Modal.java

         this.onModalDismissedListener = onModalDismissedListener;
         this.screenParams = screenParams;
         createContent();
+        setAnimation();
     }
 
     public AppCompatActivity getActivity() {
         setContentView(layout.asView());
     }
 
+    private void setAnimation() {
+        if (!screenParams.animateScreenTransitions) {
+            if (getWindow() != null) {
+                getWindow().setWindowAnimations(android.R.style.Animation);
+            }
+        }
+    }
+
     @Override
     public void push(ScreenParams params) {
         layout.push(params);

android/app/src/main/java/com/reactnativenavigation/params/parsers/AnimationParser.java

+package com.reactnativenavigation.params.parsers;
+
+import android.os.Bundle;
+
+class AnimationParser extends Parser {
+    private Bundle params;
+
+    AnimationParser(Bundle params) {
+        this.params = params;
+    }
+
+    public boolean parse() {
+        if (params.isEmpty()) {
+            return true;
+        }
+        final String animationType = params.getString("animationType", "slide-up");
+        return !animationType.equals("none") && params.getBoolean("animated", true);
+    }
+}

android/app/src/main/java/com/reactnativenavigation/params/parsers/ScreenParamsParser.java

         result.tabLabel = getTabLabel(params);
         result.tabIcon = new TabIconParser(params).parse();
 
-        result.animateScreenTransitions = params.getBoolean("animated", true);
+        result.animateScreenTransitions = new AnimationParser(params).parse();
 
         return result;
     }