* helm-files.el (helm-ff-directory-files): Use defsubst.
* helm.el: Update keymap in *after-update-hook.
* helm-bookmark.el: Toggle filename visibility with C-] for consistence with other sources.
* helm.el (helm-output-filter--post-process): Don't update keymap it is done in *after-update-hook.
* helm-command.el (helm-M-x): Now prefix arg can't be set before calling M-x.
Issue #398 Prevent running helm-source--ff-file-name-history ouside of context.
* helm-files.el (helm-source--ff-file-name-history): Renamed with *--.
Prevent running this source outside of helm.
Add docstring.