Preserve status states on updates. UI layer refactoring.

Some things were pulled out of adapters to fragments. New classes were introduced - StatusViewData and NotificationViewData. They not only have view state in them but also help decoupling.
Because introducing parallel model list requires a lot of synchronisation PairedList was added.
Also synchronisation between fragments and adapters is quiet tedious and error-prone and should be replaces with better solution.
Oh, I also couldn’t resist and fixed bug with buttons animation in the same commit.

app/src/main/java/com/keylesspalace/tusky/util/ViewDataUtils.java

@@ -0,0 +1,78 @@
+package com.keylesspalace.tusky.util;
+
+import android.arch.core.util.Function;
+import android.support.annotation.Nullable;
+
+import com.keylesspalace.tusky.entity.Notification;
+import com.keylesspalace.tusky.entity.Status;
+import com.keylesspalace.tusky.viewdata.NotificationViewData;
+import com.keylesspalace.tusky.viewdata.StatusViewData;
+
+import java.util.ArrayList;
+import java.util.List;
+
+/**
+ * Created by charlag on 12/07/2017.
+ */
+
+public final class ViewDataUtils {
+    @Nullable
+    public static StatusViewData statusToViewData(@Nullable Status status) {
+        if (status == null) return null;
+        Status visibleStatus = status.reblog == null ? status : status.reblog;
+        return new StatusViewData.Builder()
+                .setId(status.id)
+                .setAttachments(status.attachments)
+                .setAvatar(visibleStatus.account.avatar)
+                .setContent(visibleStatus.content)
+                .setCreatedAt(visibleStatus.createdAt)
+                .setFavourited(visibleStatus.favourited)
+                .setReblogged(visibleStatus.reblogged)
+                .setIsExpanded(false)
+                .setIsShowingSensitiveContent(false)
+                .setMentions(visibleStatus.mentions)
+                .setNickname(visibleStatus.account.username)
+                .setRebloggedAvatar(visibleStatus.account.avatar)
+                .setSensitive(visibleStatus.sensitive)
+                .setSpoilerText(visibleStatus.spoilerText)
+                .setRebloggedByUsername(status.reblog == null ? null : status.account.username)
+                .setUserFullName(visibleStatus.account.getDisplayName())
+                .setSenderId(status.account.id)
+                .setRebloggingEnabled(visibleStatus.rebloggingAllowed())
+                .createStatusViewData();
+    }
+
+    public static List<StatusViewData> statusListToViewDataList(List<Status> statuses) {
+        List<StatusViewData> viewDatas = new ArrayList<>(statuses.size());
+        for (Status s : statuses) {
+            viewDatas.add(statusToViewData(s));
+        }
+        return viewDatas;
+    }
+
+    public static Function<Status, StatusViewData> statusMapper() {
+        return statusMapper;
+    }
+
+    public static NotificationViewData notificationToViewData(Notification notification) {
+        return new NotificationViewData(notification.type, notification.id, notification.account,
+                statusToViewData(notification.status));
+    }
+
+    public static List<NotificationViewData>
+    notificationListToViewDataList(List<Notification> notifications) {
+        List<NotificationViewData> viewDatas = new ArrayList<>(notifications.size());
+        for (Notification n : notifications) {
+            viewDatas.add(notificationToViewData(n));
+        }
+        return viewDatas;
+    }
+
+    private static final Function<Status, StatusViewData> statusMapper =
+            new Function<Status, StatusViewData>() {
+                @Override
+                public StatusViewData apply(Status input) {
+                    return ViewDataUtils.statusToViewData(input);
+                }
+            };
+}