UTF-8 paths for shutil functions.

Do NOT merge.

To solve UTF-8 path issue on Windows.

ERROR:

    Traceback (most recent call last):
      File "C:\Python27\x86\lib\unittest\case.py", line 322, in run
        self.setUp()
      File "D:\jenkins\workspace\Test_tribler_devel_win2008r2\tribler\Tribler\Test\test_as_server.py", line 47, in setUp
        self.setUpCleanup()
      File "D:\jenkins\workspace\Test_tribler_devel_win2008r2\tribler\Tribler\Test\test_as_server.py", line 57, in setUpCleanup
        shutil.rmtree(path)
      File "C:\Python27\x86\lib\shutil.py", line 252, in rmtree
        onerror(os.remove, fullname, sys.exc_info())
      File "C:\Python27\x86\lib\shutil.py", line 250, in rmtree
        os.remove(fullname)
    WindowsError: [Error 2] The system cannot find the file specified: 'D:\\jenkins\\workspace\\Test_tribler_devel_win2008r2\\tribler\\Tribler\\Test\\test_.Tribler\\Serg\xe9HarrO'