Questions about bracket-term unicode mode.

Hello.
I am interested in RLTK recently.
As a Korean, I want to make the Korean language support.
So I tried to print Hangul(Korean characters) to the console.
But 'main' has panicked.
I managed to find that the [PNG font file](https://github.com/amethyst/bracket-lib/blob/57aac00ee07067f9f748d0273bce95e4638f0320/bracket-terminal/resources/unicode_16x16.png) caused the panic.
There is no combined hangul at all.

So, here's questions:
1. How can I append this font file?
I have some pixelated Hangul fonts that fit 16x16 size, but I do not know how this PNG file was made.
Let me know how you build this image, please?
2. It panicked at [hal\gl_common\backing\simple_console_backing.rs:119:21](https://github.com/amethyst/bracket-lib/blob/57aac00ee07067f9f748d0273bce95e4638f0320/bracket-terminal/src/hal/gl_common/backing/simple_console_backing.rs#L119)
It panicked due to `as`, and the message was not much helpful.
(`thread 'main' panicked at 'attempt to subtract with overflow'`)
How about using `TryFrom` or `TryInto` with `expect`?

Thank you.