* helm.el (helm-map): Fix index of nth actions (#558).
(helm-show-action-buffer): Show nth keys.
(helm-select-action): Allow using nth keys from action buffer.
* helm-elisp.el: Replace some C-z with C-j (#547)
* helm-files.el: same.
* helm-help.el: same.
* helm.el (helm-map): Fix comment.