Improve infrastructure.

Do more encapsulation of raw pointers, use more PrimaryMaps instead of
Vecs, add a table.rs for managing table storage.

lib/execute/Cargo.toml

@@ -20,15 +20,13 @@ lazy_static = "1.2.0"
 libc = { version = "0.2.44", default-features = false }
 errno = "0.2.4"
 cast = { version = "0.2.2", default-features = false }
+memoffset = "0.2.1"
 
 [build-dependencies]
 cmake = "0.1.35"
 bindgen = "0.44.0"
 regex = "1.0.6"
 
-[dev-dependencies]
-memoffset = "0.2.1"
-
 [features]
 default = ["std"]
 std = ["cranelift-codegen/std", "cranelift-wasm/std"]