Minor Description
It would be nice to be able to access window-change events. To my knowledge, window-change will cause 1) the COLUMNS and LINES environment variables to be updated/set and 2) a SIGWINCH will be sent to the shell.
I've played with a implementation using a Environment interface, which replaces the Map<String,String> in Shell.start. This interface provides access to the original environment map and adds the ability to register SignalListeners which will be called for all signals or a selected signal. The patch will be attached in a moment.