Business Layer; added new Get Temporary File Name function

A new function ISFileUtilities.GetTemporaryFileName() has been added to the Business Layer.

This replaces ISFileUtilities.GetTempFileName, ISFileUtilities.GetTempFileName2 and ISSupport.GetTempFileName (these functions have been obsoleted).

This function generates an unique temporary file name in the User's temporary folder.

• The folder will be the Windows Temporary Path, i.e. ISFileUtilities.TempPath.
• If fileName is blank, the File Name returned will be 'IS' plus 8 random characters.
• If fileName ends with '*', a random 8 character suffix will be added to the File Name returned.
• The file name is 'cleaned' using the ISFileUtilities.GetFileNameCleaned function.
• If the temporary File Name already exists, the name will be updated with '-n' where n is a number starting at 1 and incremented until the file name is unique.