org-agenda.el (org-agenda-get-timestamps): Use nil as `ts-date' for diary sexpressions

* org-agenda.el (org-agenda-get-todos)
(org-agenda-get-timestamps): Use nil as `ts-date' for diary
sexpressions.
org.el (org-paste-subtree): Fix typo in docstring

* org.el (org-paste-subtree): Fix typo in docstring.
org-agenda.el (org-agenda-write): Allow writing to an .org file.

* org-agenda.el (org-agenda-write): Allow writing to an .org
file.