Trait: MarionetteLib

The MarionetteLib trait should be used instead of ModelLib when Marionette
models are the primary model system. The trait will overwrite various
functions to account for the Model/Collection and their configuration.
nestedsetindex is now a default SQL placeholder

Paradox migrations now support :nestedsetindex. This functions like
counter in the sense that it's a very large unsigned number; but unlike
counter it allows NULL and defaults to null to prevent input errors from
causing damage to the nested set structure.
cachereset for Marionette

Marionette models still won't perform any caching on their own (by design)
however they will now all trigger cache rests, via Marionette cachereset.
The default behaviour is to reset the cache of static library models but
the behaviour may be customized to reset any other model system as well.