Partially implement addMutations

include/VersionedMap.h

@@ -61,8 +61,8 @@ struct VersionedMap {
   struct Mutation {
     const uint8_t *param1;
     const uint8_t *param2;
-    int param1Length;
-    int param2Length;
+    int param1Len;
+    int param2Len;
     MutationType type;
   };