Keymap for evil-execute-in-emacs-state

The key binding for evil-execute-in-emacs-state is currently defined in evil-normal-state-map. However, perhaps it makes more sense to put it in evil-motion-state-map, so as it is available in buffers that start in motion state. For example, the user might want to \b in Buffer Menu, to run the Buffer-menu-bury command.