This is a mix of exposing new things (e.g. a `Table::fill` method) and extending existing support to `externref`s (e.g. `Table::new`). Part of #929
Wasmtime Embedding API
The wasmtime crate is an embedding API of the wasmtime WebAssembly runtime.
This is intended to be used in Rust projects and provides a high-level API of
working with WebAssembly modules.
If you're interested in embedding wasmtime in other languages, you may wish to
take a look a the C embedding API instead!