The overall change is to add cell renaming, that is

The overall change is to add cell renaming, that is
	setting fancy names for cell symbols other than name matching
	"\\`[A-Z]+[0-9]+\\'" regexp .
	(ses-create-cell-variable): New defun.
	(ses-relocate-formula): Relocate formulas only for cells the
	symbols of which are not renamed, i.e. symbols whose names do not
	match regexp "\\`[A-Z]+[0-9]+\\'".
	(ses-relocate-all): Relocate values only for cells the symbols of
	which are not renamed.
	(ses-load): Create cells variables as the (ses-cell ...) are read,
	in order to check row col consistency with cell symbol name only
	for cells that are not renamed.
	(ses-replace-name-in-formula): New defun.
	(ses-rename-cell): New defun.