There were a lot of issues that arose from trying to make GUI changes
from another thread (even though we ran those functions in the right
thread). Now we store layout information until the end of the load and
make the changes then. This works much better from both a business logic
and user experience perspective.
Also prevents multiple sequences from taking focus during load and
starting a render job.
Made various changes and fixes to the task system:
- Tasks are built around QtConcurrent rather than QThread. Reduces
code complexity significantly.
- Task error reporting is now streamlined in both TaskManager and
TaskDialog.
- Moved ProjectImport/Save/LoadManager to the app/task folder