Allow one to disable email notifications at all

Problem to solve

Right now there is a discrepancy between to-dos and email notifications. While some people prefer using email notifications others prefer using the todo list. The latter want to disable email notifications at all because they just go to to-dos on a regular basis throughout the day.

Further details

Disabling email notifications would be nice for people working with the to-do list. They don't need email notifications at all, however they want to get the to-dos.

This issue assumes that “notification settings” also affect the to-do list and cannot be used to disable email notifications. If that is wrong, please close.

Proposal

One should be able to select ”None” for notification email in notification preferences.