Feature: Offline ID assignment and online synchronization

[vjekob]

Ninja should be able to assign new object IDs when offline. Intellisense should indicate offline suggestions with a different icon/color, and it should be able to detect when it goes online. After it goes online, it should sync the offline consumption, and should be able to detect if any of offline IDs are still available, and if not, it should re-assign (re-number) those that are not.