* Remove `isView` flag from CardZone
This flag is used for two purposes:
1. It is used as a check for casting to a zone to a `ZoneViewZone`;
2. Non-view zones are added to the player's zones on construction
This patch removes the `isView` flag and instead:
1. We directly cast zones to `ZoneViewZone` using a dynamic (qobject)
cast and use the result of the cast instead of the `isView` flag to
detect if we are a view zone or not;
2. The player records its own zones when they are created, simplifying
control flow.
* Review