implemented new block system

Fixes recurring design issue that the Blocks were a frequent exception to the
DAG concept. The Blocks connecting to each others inputs/outputs while not
necessarily being "dependent" on each other to produce an image continually
causes issues while trying to create a rendering code path. This redesign
should provide a more "directed" approach to the directed acyclic graph.

app/widget/timelinewidget/tool/ripple.cpp

@@ -129,9 +129,7 @@ void TimelineWidget::RippleTool::InitiateGhosts(TimelineViewBlockItem *clicked_i
       Block* block_before_ripple = track->NearestBlockBefore(earliest_ripple);
 
       // If block is null, there will be no blocks after to ripple
-      if (block_before_ripple != nullptr
-          && block_before_ripple->type() != Block::kEnd
-          && block_before_ripple->next()->type() != Block::kEnd) {
+      if (block_before_ripple != nullptr) {
         TimelineViewGhostItem* ghost;
 
         TrackReference track_ref(track->track_type(), track->Index());