Add field to expire node.
Add settings page to module and process nodes on cron.
Convert interval to be a relative date format string.
Validate that the date string is positive.
Too many parenthesisess
Some fixes. Subtract time from interval.
Do the or.
Use admin user to peform the flagging.
This module should be independent to content types.
Merge branch 'feature/409-cron-expire-flag'