Revision history for Class-Observable

1.90 Fri Feb 05 2021
	- Maintainer change and tooling update
	- Fix to prevent delete_observer() from breaking observer references
	- No more weakening of observer refs
	- Proper inside-out implementation, including DESTROY and a CLONE for thread safety
	  (please note the documentation section on DESTROY)
	- No more debug code (but debug-related functions and methods kept for backcompat)

1.04 Sat Oct 16 2004
	- Weakening of observer refs to prevent leaks (Scalar::Util required)
	- New observer_log() and observer_error() to override logging/error output

1.03 Wed Jun 16 2004
	- POD typo fix. Thanks to Dan Langille

1.02 Tue Nov 11 2003
	- Renaming of delete_observers() as delete_all_observers() (with alias for backcompat)
	- add_observer() and delete_observer() can now take more than one observer

1.01 Wed Oct 22 2003
	- POD bug fix. Thanks to forehead@4red.org

1.00 Fri May 02 2003
	- New copy_observers() method

0.03 Mon Aug 19 2002
	- New SET_DEBUG() function to toggle debugging
	- notify_observers() takes any number of parameters

0.02 Tue May 28 2002
	- Modified API to be more like java.util.Observable:
		- remove_observer( $o )  -> delete_observer( $o )
		- remove_all_observers() -> delete_observers()
		- New count_observers()

0.01 Sun May 26 2002
	- Initial version
