Gets rustc to emit arm assembly so we can run it with Magic Lantern.

TODO:

• More bindings
• Logic stress test to make sure code generation is correct
• Turn it into a Rust module

# Installs rust and rustup
curl --proto '=https' --tlsv1.2 -sSf https://sh.rustup.rs | sh
rustup target add thumbv6m-none-eabi

Compilation is done with make rinstall_qemu.