Review due/start/alarms

[WhyNotHugo]

I'd like to review how we use due/start/alarms.

Some ideas are:

• Have a filter to filter by "alarms soon", so that we can have some reminder app poll that.
• Support for adding/removing alarms (also, some default that matches the due date?)
• Filter tasks by dtstart. Personally, I'd like to, by default, filter out tasks that have a start date in future (this will probably have to be configurable).

As far as UI goes, the I'd add a middle column with alarm and recurrances.

This requires a lot of consideration, and discussion. I'll leave this open for a while for suggestions and criticism.