Improve display of long autocompletion entries, fixing #1
Do not discard NestingContainerChild instance when tabbing, fixing #278
Close command channel when shell terminates, fixing #279
Implement terminal mode-dependent key bindings

Support optional mode parameters in key specifications,
allowing standard terminal key bindings to be specified.
Convert and import all default key bindings from the
st terminal emulator (http://st.suckless.org/).
Update about dialog credits