Send Threaded Messages

This MR deals with only sending threaded messages. Showing threads will turn up in a follow up. This allows you to start a new thread by clicking reply in thread to a normal message. 

You can also do a threaded reply to a threaded message in the main timeline at the moment because those messages aren't shown in a separate thread timeline yet but will be in future.

src/models/messageeventmodel.cpp

@@ -47,6 +47,8 @@ QHash<int, QByteArray> MessageEventModel::roleNames() const
     roles[ReplyDelegateTypeRole] = "replyDelegateType";
     roles[ReplyDisplayRole] = "replyDisplay";
     roles[ReplyMediaInfoRole] = "replyMediaInfo";
+    roles[IsThreadedRole] = "isThreaded";
+    roles[ThreadRootRole] = "threadRoot";
     roles[ShowAuthorRole] = "showAuthor";
     roles[ShowSectionRole] = "showSection";
     roles[ReadMarkersRole] = "readMarkers";
@@ -586,6 +588,14 @@ QVariant MessageEventModel::data(const QModelIndex &idx, int role) const
         return eventHandler.getReplyMediaInfo();
     }
 
+    if (role == IsThreadedRole) {
+        return eventHandler.isThreaded();
+    }
+
+    if (role == ThreadRootRole) {
+        return eventHandler.threadRoot();
+    }
+
     if (role == ShowAuthorRole) {
         for (auto r = row + 1; r < rowCount(); ++r) {
             auto i = index(r);