ConfigurableExtension(PreferenceScreen) support (#163)

* initial PreferenceScreen support, works with 'NeoXXX Scans' (pt-br)

* convert EditTextPreference to json successfully

* commit what I've got

* bring back the old SharedPreferences for CustomContext, implement Toast

* put back syer's implementation

AndroidCompat/src/main/java/android/widget/Toast.java

@@ -0,0 +1,91 @@
+package android.widget;
+
+/*
+ * Copyright (C) Contributors to the Suwayomi project
+ *
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at https://mozilla.org/MPL/2.0/. */
+
+public class Toast {
+    public static final int LENGTH_LONG = 1;
+    public static final int LENGTH_SHORT = 0;
+
+    private CharSequence text;
+
+    private Toast(CharSequence text) {
+        this.text = text;
+    }
+
+    public Toast(android.content.Context context) {
+        throw new RuntimeException("Stub!");
+    }
+
+    public void show() {
+        System.out.printf("made a Toast: \"%s\"\n", text.toString());
+    }
+
+    public void cancel() {
+        throw new RuntimeException("Stub!");
+    }
+
+    public void setView(android.view.View view) {
+        throw new RuntimeException("Stub!");
+    }
+
+    public android.view.View getView() {
+        throw new RuntimeException("Stub!");
+    }
+
+    public void setDuration(int duration) {
+        throw new RuntimeException("Stub!");
+    }
+
+    public int getDuration() {
+        throw new RuntimeException("Stub!");
+    }
+
+    public void setMargin(float horizontalMargin, float verticalMargin) {
+        throw new RuntimeException("Stub!");
+    }
+
+    public float getHorizontalMargin() {
+        throw new RuntimeException("Stub!");
+    }
+
+    public float getVerticalMargin() {
+        throw new RuntimeException("Stub!");
+    }
+
+    public void setGravity(int gravity, int xOffset, int yOffset) {
+        throw new RuntimeException("Stub!");
+    }
+
+    public int getGravity() {
+        throw new RuntimeException("Stub!");
+    }
+
+    public int getXOffset() {
+        throw new RuntimeException("Stub!");
+    }
+
+    public int getYOffset() {
+        throw new RuntimeException("Stub!");
+    }
+
+    public static Toast makeText(android.content.Context context, java.lang.CharSequence text, int duration) {
+        return new Toast(text);
+    }
+
+    public static android.widget.Toast makeText(android.content.Context context, int resId, int duration) throws android.content.res.Resources.NotFoundException {
+        throw new RuntimeException("Stub!");
+    }
+
+    public void setText(int resId) {
+        throw new RuntimeException("Stub!");
+    }
+
+    public void setText(java.lang.CharSequence s) {
+        throw new RuntimeException("Stub!");
+    }
+}