Behaviros 3.12

New Behaviors:

• Set External Bitmap: Retrieves a bitmap and sets the bitmap of the associated Render Node when its action is triggered.
• Check External Resource Change: Reacts on ExternalResourceChangedEvents, reloading the resource and invoking an update if ExternalResourceMangerId  and ExternalResourceId match.
• External Bitmap Provider: Loads a bitmap at scene start from an External Resource Manager using ExternalResourceManagerId  and ExternalResourceId.

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