hyper_carray, a hyper_register implemented by a C-array

Hey @knutin,

After your nice presentation at the user group, I prepared a hyper backend implemented by NIFs, which modify a single continuous array of p^2 bytes.

I have not yet managed to integrate the tests, as I first need to get some practice with proper. However, should the implementation be correct, it appears to be the fastest backend yet.

Let me know if you're interested :)