(feature request) allow you to hide apps automatically

[Elephant-on-github]

I would like to suggest a feature that is to have a config to automatically remove certain apps from the total time count. e.g. I am on a laptop and when I lock the laptop in is in Lockapp.exe, I would like to not include this app in the time total

[herrbrixter]

This is related to #211. If you can categorize apps, you can specify which category to ignore.