org-table.el: Switch back to the old default for `org-table-number-regexp'

* org-table.el (org-table-number-regexp): Allow the user to
set it to a new regexp, which allows commas as decimal mark.
The default is to not use this setting, but the one before
commit 7ff8c1, which has ben reverted.

See the discussion here:
http://thread.gmane.org/gmane.emacs.orgmode/59389

lisp/org-table.el

@@ -138,6 +138,8 @@ Other options offered by the customize interface are more restrictive."
 		 "^[-+]?[0-9.]+\\([eEdD][-+0-9]+\\)?$")
 	  (const :tag "Very General Number-Like, including hex"
 		 "^\\([<>]?[-+^.0-9]*[0-9][-+^.0-9eEdDx()%]*\\|\\(0[xX]\\)[0-9a-fA-F]+\\|nan\\)$")
+	  (const :tag "Very General Number-Like, including hex, allows comma as decimal mark"
+		 "^\\([<>]?[-+^.,0-9]*[0-9][-+^.0-9eEdDx()%]*\\|\\(0[xX]\\)[0-9a-fA-F]+\\|nan\\)$")
 	  (string :tag "Regexp:")))
 
 (defcustom org-table-number-fraction 0.5