* Add a .gitattributes file specifying LF-style line endings.
This is similar to [Rust's .gitattributes file] though simplified.
Most of our source and documentation files already used LF-style line
endings, including *.cs files, so this makes things more consistent.
[Rust's .gitattributes file]: https://github.com/rust-lang/rust/blob/master/.gitattributes
* Remove UTF-8 BOMs in *.cs files.
Most of our *.cs files don't have UTF-8 BOMs, so this makes things more
consistent.
This commit implements an initial WASI C API that can be used to instantiate
and configure a WASI instance from C.
This also implements a `WasiBuilder` for the C# API enabling .NET hosts to bind
to Wasmtime's WASI implementation.
