handling multibyte credentials (see issue #60), added known problems section to README
changed README text for missing values
updated changelog
changed multibyte credential handling to cover not only ini settings but also credentials provided as parameters to ExcelBook::__construct()
changed indent spaces to tab
added test for licensing infos
reverted multibyte handling of ExcelBook:__construct() parameters due to errors if parameters already ISO-8859-1 coded
Merge pull request #88 from johmue/master

handling multibyte credentials