Review pass for base58check implementation (#22)

Author: shikokuchuo

src/base2.c

@@ -75,9 +75,7 @@ static bool b58tobin(void *bin, size_t *binszp, const char *b58, size_t b58sz) {
   size_t i, j;
   unsigned zerocount = 0;
 
-  for (i = 0; i < outisz; ++i) {
-    outi[i] = 0;
-  }
+  memset(outi, 0, sizeof(outi));
 
   for (i = 0; i < b58sz && b58u[i] == '1'; ++i)
     ++zerocount;