Integrate prior art from Typic

[Shnatsel]

Typic seems to be pushing the envelope on what kind of transmutes can be made possible in safe Rust.

I'm opening this issue so that you're aware of it and can integrate it in the RFC as prior art.

[rylev]

#5 addresses this as it's directly inspired by Typic

[jswrenn]

Going to close this as completed! TransmuteFrom is essentially typic, but implemented in the compiler and far more powerful.