v2.2.0

• Brand new example.
• Add SortPathDelegate. Fix #24 .
• Using zoom page transition for viewer.
• Slightly add padding to viewer's assets list view.
• Migrate elevation and color to material rendering. Fix #26 .
• Request thumb only when request type is not audio.
• Force request title for audio type asset.
• Expose AssetType enum.
• Fix issue with request type.