Add features for lising:

* Introduce default task
* Make scenario's for all existing listings
refactor thor method, simplified logic
Scenario for sorting introduced.
Failing scenario: Todo: sort by date
Introduce profiles to ignore @todo
Add listdone, listproj and listcon

* To list done items, projects and contexts
* Refactored item-count into a re-usable step
Alignment and whitespace
Fix feature that got broken in spacing-cleanup.
Feature to add new items
Feature for "do" task
Support for marking multiple items as done.

* Refactored scenarios to reduce duplication
Feature to "Undo" items
Feature to allow priorities
Feature to remove priorities
Feature to append text to items
Feature to prepend text to an item
Feature to replace lines
Feature to remove items
Feature to move items between files
Add TODO in code: merge to classes