Release 2.3.0

In this release, we:

- Added support for CP932 detection (thanks to @hashy).
- Fixed an issue where UTF-8 with a BOM would not be detected as UTF-8-SIG (#8).
- Modified `chardetect` to use `argparse` for argument parsing.
- Moved docs to a `gh-pages` branch.  You can now access them at http://chardet.github.io.