org-sort: Read compare-func in interactive calls

org-sort: Read compare-func in interactive calls

* lisp/org-macs.el (org-read-function): New function.
* lisp/org-table.el (org-table-sort-lines): Make WITH-CASE an optional
argument to match org-sort-entries and org-sort-list.
* lisp/org.el (org-sort-entries):
* lisp/org-table.el (org-table-sort-lines):
* lisp/org-list.el (org-sort-list): Read COMPARE-FUNC when called
interactively rather than being restricted to the default behavior of
sort-subr's PREDICATE parameter.  Only prompt for for GETKEY-FUNC and
COMPARE-FUNC during an interactive call, like org-table-sort-lines
already did for GETKEY-FUNC, but use an argument rather than relying
on the brittle called-interactively-p.

Suggested-by: Zhitao Gong <zhitaao.gong@gmail.com>
<https://lists.gnu.org/archive/html/emacs-orgmode/2017-05/msg00040.html>