thdat: Add support for th105 and th123

Hisoten data file structure is different from ZUN's, so some part of the
code had to be changed.
Merge pull request #1 from VBChunguk/master

thdat: Add support for th105 and th123

Personally, I don't believe that we necessarily need to have unpacking support for Tasofro games in a tool that is supposed to exclusively cover ZUN games. Judging from the fact that [we previously had support for th075 which was later removed without stating any reason](https://github.com/thpatch/thtk/commit/66c00a9d521b8868edb23a3c67af0a76ea224c22), this also seems to have been xarnonymous' intent.

However, I've retired from active Touhou patching a few months ago, and therefore, this shouldn't really be my decision anymore. There already are enough forks of thtk with different features out there, and the last thing we need is one more of those.

It would have been nice, though, if you had ensured that Shift-JIS filenames are always converted into some sort of Unicode encoding before passing them to `fopen()` in `thtk_io_open_file()`. Right now, this causes various undefined errors when running on non-Shift-JIS locales.