Remove sanitize_title

[phihag]

Currently, each extractor calls sanitize_title in it's own and even makes up its own stitle. We should do both steps in process_info for all extractors.

title should be the original title (and we can assert isinstance(title, unicode)).
sanitized_title should be a title one can use in file names (i.e. without slash, and on Windows, without multiple RTL/LTR marks)
We can then make up a simplified title ascii_title for maximum compatibility.