- first pass at using paypal IPN to handle payment status notifications
  from paypal. eliminates need for manual download of paypal history
  to update league payment status. updates now occur automatically and
  nearly immediately.
- TODO: add database table for paypal tran history
- TODO: add support for donation cumulative total instead of simple
  binary paid field for league registration

	modified:   league-manager.php registration.php
- add ability for paypal IPN to update cumulative donation total
- add new wp_lm_paypal table to log paypal IPN transaction status
- add donation total to rosters page for leagues with donation button
- remove player user_account from donation custom fields... possible
  security risk for person donating to learn user account?

	modified:   league-manager.php registration.php rosters.php
		utilities.php