Add lots of new features
- pagerdutycron.php: Email now contains last 7 days incidents
- pagerdutycron.php: Email now contains next 4 weeks of schedule info
- pagerdutycron.php: Can now just email person ending and starting in schedule
- pagerduty.php: Add functions for above features
- pagerduty.php: Add function for irccat to ask for next N weeks of schedule
- Beautify README