Plugins Animation Sequence Selector

- Add special function to manually load json preset for external plugin. Activated as string param "LoadJSONAtTargetAtomPlugin" with format as "AtomName FullPluginName JSONFilePath", new line separated.
Example:
Person
plugin#5_ToumeiHitsuji.SlapStuff
Saves/PluginData/ToumeiHitsuji/SlapStuff/Presets/FemSlapsFixed2.json

- Fix null reference on first load, was checking not existing save.
- Fix fade don't work, when overlay plugin wasn't registered if this plugin loaded first then overlay plugin, on scene start.