PHPOffice/PHPExcel — pull request #382 by frost-nzcr4 (2014-06-02 07:22:35+00:00)
Title: Move the rules of worksheet name restriction to a specific writer

The dirty implementation, it could be refactored to call `Specific_Worksheet_Writer.prepareSheetName` within `Worksheet.getTitle()` by injecting a writer to the Worksheet class.