fixed bugs, added more tests

dist/spritz.js

@@ -84,7 +84,7 @@ spritz._absorbByte = function _absorbByte(b, state) {
 
 spritz._absorbNibble = function _absorbNibble(x, state) {
     if (state.a === N_OVER_TWO_FLOOR){
-        spritz.shuffle(state);
+        spritz._shuffle(state);
     }
 
     util.swap(state.S, state.a, util.madd(N_OVER_TWO_FLOOR, x));