need feature:AssetBundleLoader the list updated then reload AB on next loading.

[sassembla]

• using Asset from AssetBundle.
• the ABList is changed, which contains the change of using Asset.
• Asset from AssetBundle is still valid.
• When load Asset again, new Asset should be load from new AB.

[sassembla]

feature added at 1cde3e387ad172e07345279d0bb7b32152eb2a09