Use :inverse-video t for `org-date-selected'.

Use :inverse-video t for `org-date-selected'.

* org.el (org-read-date): Set cursor-type to nil in the calendar.

* org-faces.el (org-date-selected): Use inverse video.  Don't explicitely
set bold to nil as it causes `customize-face' to show the weight property
and thus encourage the user to change it.  Warn in the docstring that using
bold might cause problems when displaying the calendar.

Using inverse video for the selected date might be too much for many
people, but with cursor-type set to nil (thanks to Toby Cubitt for this)
and with a light-weight font, we need to really highlight the selected
date -- and a simple color change is not catchy enough IMO.