Edera

* Fixed a major race condition issue with `MonitorWatcher`
* Hid stale tasks from the main monitoring UI page
* Adapted the code to SympPy 1.6

* Achieved 100% test coverage
* Got rid of system tests
* Separated the demo from the package completely
* Prevented multiple parallel instances of `MonitorWatcher` from breaking the monitor
* Upgraded `Daemon`
- Made it stop once all tests pass (in auto-testing mode)
- Made it interruptible (without signals)
- Embedded a `MonitorWatcher` into a dedicated process
* Introduced `Timer` for `Routine`s and fixed error propagation in them
* Introduced `ExtendAnnotation` for simpler declaration of tests
* Altered the behaviour of `TagFilter` a bit
* Fixed a few minor issues with third-party libraries

* Fixed stale task detection
* Improved running/failure time formatting in the monitoring UI

* Fixed monitoring snapshot core timestamp updates

* Added "stale" task detection during monitoring
* Added tooltips for the "phony" and "stale" marks in `MonitoringUI`
* Silenced storage operation errors in `MonitorWatcher`

* Fixed snapshot timestamp serialization