Review public API

[xivk]

We have been adding new features quickly, we need to review what we have done and rethink things a bit.

We need to review at least:

• [ ] Review the data provider implementation/serialization.
• [ ] Tile parsing/loading.
• [ ] Inline weight handling and weight caching, especially the API is hard to understand and breaks easily.

Don't close this issue too quickly, we don't want to release a badly designed API