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.

src/disassemble.rs

@@ -2,6 +2,7 @@ use capstone::prelude::*;
 use error::Error;
 use std::fmt::Write;
 
+#[allow(dead_code)]
 pub fn disassemble(mem: &[u8]) -> Result<(), Error> {
     let mut cs = Capstone::new()
         .x86()