This adds four commands to enter a due date date in the format [due:: YY-MM-DD] at cursor (with optional hashtags):
- Due end of this week: set to Friday of this week
- Due end of next week: set to Friday of next week
- Due end of this month: set to last day (or weekday) of this month
- Due after I'm gone: set 100 years in the future, i.e. I'm not doing this
The four options of tags to add correspond to the four commands:
- This week tag
- Next week tag
- This month tag
- Never tag
The 'Last Weekday' option toggles whether 'end of this month' should be the last weekday of the month or the last calendar day of this month.