various: implemented multiple project support

This required various changes to various parts of the infrastructure (mostly
using paths to finding the "root project" of any given object throughout).
Now theoretically infinite projects can be opened and accounted for at any
given time.

app/widget/nodeview/nodeviewundo.cpp

@@ -20,6 +20,8 @@
 
 #include "nodeviewundo.h"
 
+#include "project/item/sequence/sequence.h"
+
 OLIVE_NAMESPACE_ENTER
 
 NodeEdgeAddCommand::NodeEdgeAddCommand(NodeOutput *output, NodeInput *input, QUndoCommand *parent) :
@@ -59,6 +61,11 @@ void NodeEdgeAddCommand::undo_internal()
   done_ = false;
 }
 
+Project *NodeEdgeAddCommand::GetRelevantProject() const
+{
+  return static_cast<Sequence*>(output_->parentNode()->parent())->project();
+}
+
 NodeEdgeRemoveCommand::NodeEdgeRemoveCommand(NodeOutput *output, NodeInput *input, QUndoCommand *parent) :
   UndoCommand(parent),
   output_(output),
@@ -95,6 +102,11 @@ void NodeEdgeRemoveCommand::undo_internal()
   done_ = false;
 }
 
+Project *NodeEdgeRemoveCommand::GetRelevantProject() const
+{
+  return static_cast<Sequence*>(output_->parentNode()->parent())->project();
+}
+
 NodeAddCommand::NodeAddCommand(NodeGraph *graph, Node *node, QUndoCommand *parent) :
   UndoCommand(parent),
   graph_(graph),
@@ -114,6 +126,11 @@ void NodeAddCommand::undo_internal()
   graph_->TakeNode(node_, &memory_manager_);
 }
 
+Project *NodeAddCommand::GetRelevantProject() const
+{
+  return static_cast<Sequence*>(graph_)->project();
+}
+
 NodeRemoveCommand::NodeRemoveCommand(NodeGraph *graph, const QList<Node *> &nodes, QUndoCommand *parent) :
   UndoCommand(parent),
   graph_(graph),
@@ -156,6 +173,11 @@ void NodeRemoveCommand::undo_internal()
   edges_.clear();
 }
 
+Project *NodeRemoveCommand::GetRelevantProject() const
+{
+  return static_cast<Sequence*>(graph_)->project();
+}
+
 NodeRemoveWithExclusiveDeps::NodeRemoveWithExclusiveDeps(NodeGraph *graph, Node *node, QUndoCommand *parent) :
   UndoCommand(parent)
 {
@@ -166,8 +188,13 @@ NodeRemoveWithExclusiveDeps::NodeRemoveWithExclusiveDeps(NodeGraph *graph, Node
   remove_command_ = new NodeRemoveCommand(graph, node_and_its_deps, this);
 }
 
+Project *NodeRemoveWithExclusiveDeps::GetRelevantProject() const
+{
+  return remove_command_->GetRelevantProject();
+}
+
 NodeCopyInputsCommand::NodeCopyInputsCommand(Node *src, Node *dest, bool include_connections, QUndoCommand *parent) :
-  UndoCommand(parent),
+  QUndoCommand(parent),
   src_(src),
   dest_(dest),
   include_connections_(include_connections)
@@ -175,14 +202,14 @@ NodeCopyInputsCommand::NodeCopyInputsCommand(Node *src, Node *dest, bool include
 }
 
 NodeCopyInputsCommand::NodeCopyInputsCommand(Node *src, Node *dest, QUndoCommand *parent) :
-  UndoCommand(parent),
+  QUndoCommand(parent),
   src_(src),
   dest_(dest),
   include_connections_(true)
 {
 }
 
-void NodeCopyInputsCommand::redo_internal()
+void NodeCopyInputsCommand::redo()
 {
   Node::CopyInputs(src_, dest_, include_connections_);
 }

app/widget/nodeview/nodeviewundo.h

@@ -39,6 +39,8 @@ class NodeEdgeAddCommand : public UndoCommand {
 public:
   NodeEdgeAddCommand(NodeOutput* output, NodeInput* input, QUndoCommand* parent = nullptr);
 
+  virtual Project* GetRelevantProject() const override;
+
 protected:
   virtual void redo_internal() override;
   virtual void undo_internal() override;
@@ -62,6 +64,8 @@ public:
   NodeEdgeRemoveCommand(NodeOutput* output, NodeInput* input, QUndoCommand* parent = nullptr);
   NodeEdgeRemoveCommand(NodeEdgePtr edge, QUndoCommand* parent = nullptr);
 
+  virtual Project* GetRelevantProject() const override;
+
 protected:
   virtual void redo_internal() override;
   virtual void undo_internal() override;
@@ -77,6 +81,8 @@ class NodeAddCommand : public UndoCommand {
 public:
   NodeAddCommand(NodeGraph* graph, Node* node, QUndoCommand* parent = nullptr);
 
+  virtual Project* GetRelevantProject() const override;
+
 protected:
   virtual void redo_internal() override;
   virtual void undo_internal() override;
@@ -94,6 +100,8 @@ public:
                     const QList<Node*>& nodes,
                     QUndoCommand* parent = nullptr);
 
+  virtual Project* GetRelevantProject() const override;
+
 protected:
   virtual void redo_internal() override;
   virtual void undo_internal() override;
@@ -112,11 +120,13 @@ public:
                               Node* node,
                               QUndoCommand* parent = nullptr);
 
+  virtual Project* GetRelevantProject() const override;
+
 private:
   NodeRemoveCommand* remove_command_;
 };
 
-class NodeCopyInputsCommand : public UndoCommand {
+class NodeCopyInputsCommand : public QUndoCommand {
 public:
   NodeCopyInputsCommand(Node* src,
                         Node* dest,
@@ -128,7 +138,7 @@ public:
                         QUndoCommand* parent = nullptr);
 
 protected:
-  virtual void redo_internal() override;
+  virtual void redo() override;
 
 private:
   Node* src_;