Thanks to Jason Merrill. Screen now has a very large 'configure' script. Stackable overlay planes. All commands are available even if you work with an overlay. Unification of key bindings and screen commands.
All keys now generate commands.
Ansi parser speedup code resulting in much faster output of text. Commands now directly affect the current window. The 'set' keyword no longer exists. Emacs style isearch added to copy mode. New command 'silence'.