Enhance Filters displayed in UI.

Filtering:

:: The first entry should always be the "Switch off all filters" option. This doesn't hinder you presetting an actual filter as default values.

:: Every filter entry has a defining class within its <li> container. This will enable me to add little visual hints about a filter's nature (e.g. color coding, icons).

:: I proposed some more filters I would find useful for managing Operations. And I tried to change the wording so that we can spare obvious terms like "Only".