Operating on multiple tasks

Hi again!
Are you open to the idea of making it possible to operate on multiple tasks in one go?
I'm thinking something like this:
```
clikan add "Buy toilet paper" "Feed cat" "Fold laundry" # Creates three tasks
clikan promote 1 2 # Promotes two tasks
clikan delete 1 2 3 # Deletes three tasks
```

If you're ok with such a behavior change then I'll be happy to add it in myself. 