File names are ugly in windows

[Chronial]

The default title sanitation replaces spaces with underscores, which is probably what most users want in Linux, but in Windows the titles should definitely keep their spaces.

I‘d be happy to provide a pull request for this, I’m just not sure how you would prefer this: I could either fix the default sanitation or add a new one (%(ntitle)s) that produces nicer titles.

[phihag]

That's not a Windows-specific issue; both Windows and Linux can handle spaces in file names fine. We had spaces in at one point, but disabled them. I'll look up why.

[FiloSottile]

Well, basically we don't have them in anymore because of me and my too much strict sanitize_filename(). I hate filesystems (blame me) and probably screwed.

Not allowed now are

char in u' .\\/|?*<>:"' or ord(char) < 32

probably space and dot are OK. Can I go with the patch? Even if this will break some "already downloaded" checks?

The others aren't according to Wikipedia, but should we replace them with something else than _?

[phihag]

Should be fixed with #502, and will be in the next release.