Moving to php-calendar.org

I've had php-calendar.com and php-calendar.org for years now. I'm moving everything over to php-calendar.org and getting rid of php-calendar.com.

In other news, php-calendar 2.1 is coming along quite well. I'm focusing mainly on polishing the UI. Markdown is now supported in the descriptions. The week view has been brought to parity with the month view. I'm working on improving the updater and installer. If there's anything you think is important for 2.1, please add it at https://github.com/sproctor/php-calendar/issues