stub out more stuff

Author: Gankra

ffi.md

@@ -7,6 +7,17 @@ Unsafe Rust. TURPL does not assume you have read TRPL, but does assume you know
 the basics of the language and systems programming. We will not explain the
 stack or heap, we will not explain the syntax.
 
+## Sections
+
+* [Data Layout](data.html)
+* [Ownership and Lifetimes](lifetimes.html)
+* [Conversions](conversions.html)
+* [Uninitialized Memory](uninitialized.html)
+* [Ownership-oriented resource management (RAII)](raii.html)
+* [Concurrency](concurrency.html)
+* [Interfacing with other languages (FFI)](ffi.html)
+* [Eliminating the Runtime (no_std)](no_std.html)
+
 ## A Tale Of Two Languages
 
 Rust can be thought of as two different languages: Safe Rust, and Unsafe Rust.