Fix io_file_is_empty() behaviour when file starts with a newline.
Fix io_file_is_empty() behaviour when file starts with a newline.

Read second byte if the first byte is a newline character to ensure the
file doesn't contain any further data.

Signed-off-by: Lukas Fleischer <af90e31281d8305af43dc616c5aaca3c7165f8a7@cryptocrack.de>

lfos/calcurse,dunecn/calcurse,lfos/calcurse,dunecn/calcurse,lfos/calcurse