WASI prototype design, implementation, and documentation.

This adds documents describing the WASI Core API, and an implementation in
Wasmtime.

docs/WASI-documents.md

@@ -0,0 +1,22 @@
+# WASI Document Guide
+
+To get started using WASI, see [the intro document](WASI-intro.md) and
+[the tutorial](WASI-tutorial.md).
+
+For more detail on what WASI is, see [the overview](WASI-overview.md).
+
+For specifics on the API, see the [API documentation](https://github.com/CraneStation/wasmtime-wasi/blob/wasi/docs/WASI-api.md).
+Additionally, a C header file describing the WASI API is
+[here](https://github.com/CraneStation/reference-sysroot-wasi/blob/misc/libc-bottom-half/headers/public/wasi/core.h).
+
+For some discussion of capability-based design, see the [Capabilities document](WASI-capabilities.md).
+
+For some discussion of WASI's design inspiration, see the [Background document](WASI-background.md).
+
+For background on some of the design decisions in WASI, see [the rationale](WASI-rationale.md).
+
+For some ideas of things that we may want to change about WASI in the
+short term, see the [possible changes](WASI-some-possible-changes.md) document.
+For longer-term ideas, see the [possible future features](WASI-possible-future-features.md)
+document.
+