number_format() causes problem when using other notations (US/GER)

```
Using number_format() to output the values can cause problems, because
number_format() uses the Anglo-Saxon notation by default, which means a
comma for the thousands separator and a point for the decimals.

In other countries you normally use them the other way around. So please
make number_format() configurable or output the values in a raw format.

Thank you
```

Original issue reported on code.google.com by `johannes...@gmail.com` on 14 Apr 2010 at 8:46

Start by locating the number_format() entry point and checking how its output is used for spreadsheet values. Determine whether configurable separators or raw values are expected, then verify that US and German-style notation no longer causes the reported problem.

Written by the indexing model from the issue text.