[Lazarus] fpspreadsheet excel5 export

[Felipe Monteiro de Carvalho]

Excel 5 does not support unicode. My original code would just store
all strings as iso-latin-1, so I am surprized that any letters are
stored at all. You only used letters outside iso-latin-1, so they
should all show up wrong.

There is a table comparing the formats here:
http://wiki.lazarus.freepascal.org/FPSpreadsheet#Current_Progress

-- 
Felipe Monteiro de Carvalho