whoops, bad hex decoder

test/ristretto.cxx

@@ -14,9 +14,9 @@
 using namespace decaf;
 
 inline int hexi(char c) {
-    if (c >= '0' && c < '9') return c-'0';
-    if (c >= 'a' && c < 'f') return c-'a'+0xa;
-    if (c >= 'A' && c < 'F') return c-'A'+0xa;
+    if (c >= '0' && c <= '9') return c-'0';
+    if (c >= 'a' && c <= 'f') return c-'a'+0xa;
+    if (c >= 'A' && c <= 'F') return c-'A'+0xa;
     return -1;
 }