Some filter options

Thank you for this very helpful extension. I made some changes that I think would be useful for more people. They where motivated by my own workflow which is based off the FVP-Timemanagement-System. For that I needed to keep control of the order of the list and only show tasks above a given priority.

In addition a made some obvious changes to use your modernized interface of logger (as it didn't work in its current state) and added a filter to hide completed (unarchived) tasks as it should be a helpful partial implementation of #15.

All (feature-)changes are done behind configuration options with the default value being the previous behavior and only showing on an "expert"-Settings-level.

Hope these changes find your pleasing. If you have any questions or requests that I make changes, don't hesitate to ask.