various improvements to import process and project management

app/core.cpp

@@ -74,6 +74,8 @@ void Core::Start()
     startup_project_ = args.first();
   }
 
+  // Declare custom types for Qt signal/slot syste
+  DeclareTypesForQt();
 
 
   //
@@ -174,3 +176,8 @@ void Core::AddOpenProject(ProjectPtr p)
   open_projects_.append(p);
   emit ProjectOpened(p.get());
 }
+
+void Core::DeclareTypesForQt()
+{
+  qRegisterMetaType<Task::Status>("Task::Status");
+}