Fixed crash with call to tzname()

Fixed `'NoneType' object has no attribute 'encode'` crash with calls to tzname().
Added --quiet option

Added -u and --quiet option to disable all non-debug messages.
Added --icon argument

Added --icon argument to specify the icon to use in notifications.
Corrected tzname crash fix

Corrected the tzname crash fix by excepting the error thrown by tzname, because the previous fix avoided setting the timezone altogether with a poorly written boolean check.
Merge pull request #2 from nejsan/master

Crash fix, --quiet and --icon options