Compile a simple function (#2)

* Implement basics.

* Execute code

* Add wasm2wat test cases.

* abi_loc_for_arg for stack.

* Assert that sp_depth is 0 at the epilogue

* Do 32bit add.

* Assert that RAX can be used as a scratch register

* Reuse assembler.

* Align stack slots.

Cargo.toml

@@ -15,6 +15,7 @@ wasmparser = "0.21.6"
 capstone = "0.5.0"
 failure = "0.1.3"
 failure_derive = "0.1.3"
+wabt = "0.7"
 
 [badges]
 maintenance = { status = "experimental" }