Fixed warnings in FlexBuffers.java

- Missing return statement <- bug!
- Missing hashCode function.

Change-Id: I6333cac72adf8ead92ab2e6c7215650ce4571a73

java/com/google/flatbuffers/FlexBuffers.java

@@ -393,7 +393,7 @@ public class FlexBuffers {
                     case FBT_NULL: return 0;
                     case FBT_STRING: return Long.parseLong(asString());
                     case FBT_VECTOR: return asVector().size();
-                    case FBT_BOOL: readInt(bb, end, parentWidth);
+                    case FBT_BOOL: return readInt(bb, end, parentWidth);
                     default:
                         // Convert other things to uint.
                         return 0;
@@ -792,6 +792,10 @@ public class FlexBuffers {
 
             return ((Key) obj).end == end && ((Key) obj).byteWidth == byteWidth;
         }
+
+        public int hashCode() {
+          return end ^ byteWidth;
+        }
     }
 
     /**