Changelog
- support plural day names with appostrophes (i.e. "Monday's 9am to 5 pm")
- support listing specific days (i.e. "Mondays, Tuesdays, Thursdays 9am to 5 pm")
- add support for commonly used shortcuts like "7 days a week" "daily" "weekdays" "business days" "weekends" .etc
- treat no specified days (i.e. "9am to 5pm") the same as "every day"
- made parsing of day names more robust