Silence a good bunch of Intel warnings

Note that some pawns and material info has been switched
to int from int8_t.

This is a waste of space but it is not clear if we have a
faster or slower code (or nothing changed), some test should be
needed.

Few warnings still are alive.

Signed-off-by: Marco Costalba <mcostalba@gmail.com>

src/evaluate.cpp

@@ -490,7 +490,7 @@ void init_eval(int threads) {
   }
 
   for (Bitboard b = 0ULL; b < 256ULL; b++)
-      BitCount8Bit[b] = count_1s(b);
+      BitCount8Bit[b] = (uint8_t)count_1s(b);
 }