Support more wrapper classes and methods and async loading

[niraj-rayalla]

• Updated to Effekseer version 1.62c.
• More generalized manager/effect classes.
• Lots of Effekseer structs and classes are now available to use in java but only some of them are truly wrapped to avoid new java instance creation for each get call.
• Wrapped EffekseerNode , EffekseerNodeRoot, EffekseerNodeSprite, and EffekseerNodeTrack, so that runtime accessing and modification of these types is available without creating new java instance creation for each get call.
• Loading is now done through LibGDX's AssetManager.
• Loading can be synchronous or asynchronous.
• Updated README.md for the changes.