* org-capture.el (org-capture-use-agenda-date): New option.
(org-capture): Use it.
* org-agenda.el (org-agenda-capture): New command.
(org-agenda-mode-map): Bind it to `k'.
(org-agenda-menu): Add it to the menu.
* org.texi (Agenda commands): Document the new command and the
new option.
Thanks to Eric Abrahamsen who suggested this change, along with
other merging about bulk actions.