Make alignment optimization optional

Disabling alignment optimization allows preserving file order in torrent
files and closes #5652

src/base/bittorrent/torrentcreatorthread.cpp

@@ -92,7 +92,8 @@ void TorrentCreatorThread::run()
 
         if (isInterruptionRequested()) return;
 
-        libt::create_torrent newTorrent(fs, m_params.pieceSize);
+        libt::create_torrent newTorrent(fs, m_params.pieceSize, -1
+            , (m_params.isAlignmentOptimized ? libt::create_torrent::optimize_alignment : 0));
 
         // Add url seeds
         foreach (QString seed, m_params.urlSeeds) {

src/base/bittorrent/torrentcreatorthread.h

@@ -39,6 +39,7 @@ namespace BitTorrent
     struct TorrentCreatorParams
     {
         bool isPrivate;
+        bool isAlignmentOptimized;
         int pieceSize;
         QString inputPath;
         QString savePath;