Don't return lines not ending in a newline when following

Addresses #35
I don't think it should. If the file is reopened because of deletion or truncation in `tail.waitForChanges`, it will then seek to the position of the previous version of the file (which likely doesn't exist yet) in the new version just opened, and as such will miss all the lines between the 0 byte position and the current byte position. Unless there's something I missed?