Begin internal reorganization.

This begins reorganizing how translation and compilation occur, and
setting up infrastructure for imports/exports and relocations. It
splits parts out of StandaloneRuntime, forming Module, Compilation,
and Instance structs, which can be used more independently.

It also simplifies the command-line interface, in a step towards
making simple tools that just expose the functionality of the
libraries.

lib/runtime/Cargo.toml

@@ -10,3 +10,4 @@ license = "Apache-2.0"
 [dependencies]
 cretonne = { git = "https://github.com/stoklund/cretonne.git" }
 cretonne-wasm = { git = "https://github.com/stoklund/cretonne.git" }
+wasmparser = "0.13.0"