Unify Interfaces of provider classes

[masa-sony]

Interfaces of provider classes are not unified.

ClassName

current class names are as follows.

• StandardImageProvider, CloudImageProvider, EmptyImageProvider.ts
• StandardDemProvider, CloudDemProvider, FlatDemProvider.ts
• StandardB3dProvider
• RawPointCloudProvider
• vectile/StandardTileProvider

RawPointCloudProvider is strange. It should be StandardPointCloudProvider.

Members of the providers

We are going to use async/await syntax for asynchronous functions and only use two functions to define provider class as follows.

• async init({ signal: AbortSignal }):Promise<Info>
• async requestTile(z, x, y, { signal: AbortSignal }): Promise<Data>

Where

• signal is used for cancellation feature.
• Info and Data depend on the types of tiles.

[masa-sony]

• Supported ImageProvider and DemProvider: c9b7343
• Supported PointCloudProvider: 44c084e

We will support B3dProvider and VecTileProvider in a future release.