fix: invalid file seek position.

In windows, line head position does not equal previous_line head + previous_line bytesize.
But this does not occur in the file containing only LF, this occur in the file containing CR/LF.
fix ambiguous initialization for previous_seek.
Rollback previous changes.
Suppress automatically conversion EOL <-> CRLF.
Merge pull request #319 from toruuetani/spike-windows-tail-invalid-seek

Fix invalid file seek in the file containing CRLF
Merge pull request #331 from MasayukiKiyota/windows

v0.10.46 merge into windows branch
Update README.md
update gem package.
old one does not include PR331
fix : handling of non existing file in in_tail
ERROR_FILE_NOT_FOUND, ERROR_ACCESS_DENIED are mapped to ENOENT.
Avoid a shutdown problem by killing main process.
This is 'avoid', not 'fix'. but it looks work anyway.