Add existing LED matrix support

[saibatizoku]

Hello! I've recently published a crate for handling the LED matrix, which is working and can handle printing from a legacy 8x8 font collection that I've brought up to date with Unicode points.

I'm wondering if you are interested in joining efforts, as I'm currently under way to write another crate for the joystick-button, as well.

The LED matrix crate, you can find at: https://github.com/saibatizoku/sensehat-screen-rs
The fonts crate: https://github.com/saibatizoku/font8x8-rs

Cheers!

[thejpster]

Hi! This sounds excellent, and very appropriate, as I have just written a bitmap font renderer (I used 8x16) for my other project.

We could merge the functionality into one single crate, or, as I'm actually thinking about breaking my crate up into smaller pieces anyway (as the sensors drivers are generic), I could just depend on your crate and wrap it with an API similar to the one in the Python Sense HAT driver.

If you have time, please do send a PR that brings in your crate and we can look at the wrapper API after.

[saibatizoku]

Great news! I'm in favor of splitting up the functionality into separate crates, like you mention. Maybe use the sensehat crate as a top-level namespace, with "sensors"/"led-matrix"/"joystick" features?

I'm using features with sensehat-screen, because I'm writing a side-project that's a browser-based Sense HAT emulator (written with the stdweb crate), that removes the linux-framebuffer feature, and uses the rest (fonts, serde, frames, pixels).

I'll send a PR as soon as possible, and we can look at the wrapper API. Thanks!