Add time to lmud

[oubiwann]

Features:

• [ ] Add time tracking
• [ ] Support times of day
• [ ] Support times of night
• [ ] Days of week
• [ ] Months
• [ ] Support seasons
• [ ] Support years
• [ ] Room descriptions need to be augmented to show time / season changes since last description
• [ ] Player characters need to track the last time update received (only show in description if they've not seen the time change)
• [ ] Add new "time" command