Fixed some bugs with characters not recomputing

TODO: remove .variables cache from creature document, it's not viable

app/imports/api/engine/actions/doCastSpell.js

@@ -133,7 +133,7 @@ const doAction = new ValidatedMethod({
     Creatures.update({
       _id: { $in: [creature._id, ...targetIds] }
     }, {
-      dirty: true
+      $set: { dirty: true },
     });
   },
 });