Description:
------------
Creating a spreadsheet with a simple formula like =A1*10 fails unless the formula contains a trailing space



#php configuration
'./configure' \
'--enable-xml' \
'--enable-ftp' \
'--with-mysql=/usr' \
'--with-apache=../apache' \
'--with-zlib-dir=/usr/local' \
'--with-curl=/usr/local' \
'--with-jpeg-dir=/usr/local' \
'--with-png-dir=/usr/local' \
'--enable-track-vars' \
'--with-pspell=/usr/local' \
'--with-dom=/usr/local' \
'--enable-track-vars' \
'--with-msession' \
'--enable-pcntl' 

Reproduce code:
---------------
<?php
require_once 'Spreadsheet/Excel/Writer.php';

$workbook = new Spreadsheet_Excel_Writer();
$workbook->send('test.xls');

$worksheet =& $workbook->addWorksheet('bug');

//data cell
$worksheet->write(0, 0, 2);

//simple formula, no trailing space - FAILURE
$worksheet->write(1, 1, "this fails");
$worksheet->write(1, 2, "=A1*10");

//simple formula, with trailing space - SUCCESS
$worksheet->write(2, 1, "this works");
$worksheet->write(2, 2, "=A1*10 ");


//close and send sheet
$workbook->close();
?>

Expected result:
----------------
expect formula =A1*10 in cell C2 of returned spreadsheet

Actual result:
--------------
cell C2 contains following text
Sintactic error: *, lookahead: , current char: 3