Adding the rest of files:

- ASM is disabled
- Neug needs full rewrite
- Flash is based on PiMoroni 4MB flash (needs adjust)

Signed-off-by: Pol Henarejos <pol.henarejos@cttc.es>

mod.h

@@ -0,0 +1,3 @@
+void mod_reduce (bn256 *X, const bn512 *A, const bn256 *B,
+		 const bn256 *MU_lower);
+void mod_inv (bn256 *X, const bn256 *A, const bn256 *N);