Fix #26 Universal newline in open file

`codecs.open` not support universal newline when encoding to
utf-8, change to `io.open`, which is the same as `open` in
Python3.x.

More detailed to see
[PEP 278](http://legacy.python.org/dev/peps/pep-0278/) and
[PEP 3116](http://legacy.python.org/dev/peps/pep-3116/).