Fix unicode in password and add test
    
    After a long discussion with ``@jcline`` and as he pointed out that using
    ``to_unincode`` is a really bad option for storing password since after
    unicoding some non-ascii value it starts giving the same character. This could
    be really harmful for security reasons.
    
    The tests are provided to check the same that things don't break on entering
    any non-ascii characters.
    
    Signed-off-by: Farhaan Bukhsh <farhaan.bukhsh@gmail.com>