+2012-11-09 Vincent Belaïche <vincentb1@users.sourceforge.net>
+
+ * ses.el: symbol to coordinate mapping is made by symbol property
+ `ses-cell'. This means that the same mapping is done for all SES
+ sheets. That is good enough for cells with standard A1 names, but
+ not for named cell. So a hash map is added for those
+ latter.
+ (defconst ses-localvars): added local variable ses--named-cell-hashmap
+ (ses-sym-rowcol): Use hashmap for named cell.
+ (ses-is-cell-sym-p): New defun.
+ (ses-decode-cell-symbol): New defun.
+ (ses-create-cell-variable): Add cell to hashmap when name is not A1-like.
+ (ses-rename-cell): Check that cell new name is not already in
+ spreadsheet with the use of ses-is-cell-sym-p
+ (ses-rename-cell): Use hash map for named cells, but accept also
+ renaming back to A1-like.
+