bootstrap: Add a bunch of Cargo.toml files

These describe the structure of all our crate dependencies.

src/libsyntax/Cargo.toml

@@ -0,0 +1,16 @@
+[package]
+authors = ["The Rust Project Developers"]
+name = "syntax"
+version = "0.0.0"
+
+[lib]
+name = "syntax"
+path = "lib.rs"
+crate-type = ["dylib"]
+
+[dependencies]
+arena = { path = "../libarena" }
+fmt_macros = { path = "../libfmt_macros" }
+serialize = { path = "../libserialize" }
+term = { path = "../libterm" }
+log = { path = "../liblog" }