fixes fail to load _io module in Python 2.6

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
remove debian directory

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>
increase version and update documents

Signed-off-by: Kouhei Maeda <mkouhei@palmtb.net>