Raise an error if the file is erased while following

[Davd96]

Actually if the file is deleted while pytailer is listening it dont raise any error and not restart reading in case the file is created again. So the thread is completely blocked.

[six8]

self.file may be a stream instead of a file with a name. So self.file.name might result in an attribute error. There are a couple of ways I can think of to handle this:

1. If getattr(self.file, "name"), then assume it's a file and check for existence. However, this could be an expensive call on a long file since it will cause an extra disk read for every single line.
2. Do a non-blocking readline and only yield something was read. This might be able to be done with select. I'm not certain how it will react if the file disappears. This will be a little more complex and might involve some more refactoring, but it should result in the best experience.

I'm inclined to choose option 2. Since you opened this pull request 5 years ago, you probably don't care anymore 😅. I'll see about fixing this. Thanks for the submission!