Limiting Gizmo Instances

Say you are using WP-Gizmos in a WP-as-a-CMS environment, and you don't want the editors to make a mistake by adding more instances of a Gizmo than the design would allow.

__Introducing Gizmo Limits!__ By simply adding an array to your gizmo file, you can limit the number of Gizmos of a type that can be added.

`sample-gizmo-plugin.php` has been updated to show an example.