* ses.el (ses-goto-print): Use move-to-column rather than

* ses.el (ses-goto-print): Use move-to-column rather than
	forward-char.
	(ses-print-cell): Use string-width, truncate-string-to-width,
	delete-region rather than length, substring, delete-char.
	(ses-setup): Set inhibit-point-motion-hooks to t.  Calculate
	position by actually moving point rather than just using unibyte
	character length.
	(ses-mode): Set indent-tabs-mode to nil.
	(ses-center): Use string-width rather than length.