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/project/project.cpp

@@ -30,7 +30,9 @@
 
 OLIVE_NAMESPACE_ENTER
 
-Project::Project()
+Project::Project() :
+  is_modified_(false),
+  autorecovery_saved_(true)
 {
   root_.set_project(this);
 }
@@ -156,4 +158,32 @@ QList<ItemPtr> Project::get_items_of_type(Item::Type type) const
   return root_.get_children_of_type(type, true);
 }
 
+bool Project::is_modified() const
+{
+  return is_modified_;
+}
+
+void Project::set_modified(bool e)
+{
+  is_modified_ = e;
+  autorecovery_saved_ = !e;
+
+  emit ModifiedChanged(is_modified_);
+}
+
+bool Project::has_autorecovery_been_saved() const
+{
+  return autorecovery_saved_;
+}
+
+void Project::set_autorecovery_saved(bool e)
+{
+  autorecovery_saved_ = e;
+}
+
+bool Project::is_new() const
+{
+  return !is_modified_ && filename_.isEmpty();
+}
+
 OLIVE_NAMESPACE_EXIT