This change adds an `--enable-simd` flag to the binaries in this project. This allows the ISA `enable_simd` flag to be set and to configure the validation configuration used by wasmparser to allow SIMD instructions.
This adds documents describing the WASI Core API, and an implementation in Wasmtime.
This follows a similar change to Cranelift made here: https://github.com/CraneStation/cranelift/pull/660