* helm-imenu.el: Use helm-execute-action-at-once-if-one and quit.
* helm-regexp.el: Remove obsolete browse code.
* helm-aliases.el: Remove old aliases.
* helm-config.el: Update autoloads.
* helm.el (helm-split-window-default-fn): Prevent displaying helm-buffer in a dedicated window.
(helm-window-in-direction): New use it.
(helm-prevent-switching-other-window): Allow switching back to a dedicated window.