Remove all checked in *.wasm files to the repo (#563)

* Tidy up the `hello` example for `wasmtime`

* Remove the `*.wat` and `*.wasm` files and instead just inline the
  `*.wat` into the example.

* Touch up comments so they're not just a repeat of the `println!`
  below.

* Move `*.wat` for `memory` example inline

No need to handle auxiliary files with the ability to parse it inline!

* Move `multi.wasm` inline into `multi.rs` example

* Move `*.wasm` for gcd example inline

* Move `*.wat` inline with `import_calling_export` test

* Remove checked in `lightbeam/test.wasm`

Instead move the `*.wat` into the source and parse it into wasm there.

* Run rustfmt

crates/lightbeam/examples/test.rs

@@ -1,34 +1,16 @@
 use lightbeam::translate;
-use std::fs::File;
-use std::io;
-use std::io::Read;
-use std::path::Path;
 
-fn read_to_end<P: AsRef<Path>>(path: P) -> io::Result<Vec<u8>> {
-    let mut buffer = Vec::new();
-    if path.as_ref() == Path::new("-") {
-        let stdin = io::stdin();
-        let mut stdin = stdin.lock();
-        stdin.read_to_end(&mut buffer)?;
-    } else {
-        let mut file = File::open(path)?;
-        file.read_to_end(&mut buffer)?;
-    }
-    Ok(buffer)
-}
+const WAT: &str = r#"
+(module
+  (func (param i32) (param i32) (result i32) (i32.add (get_local 0) (get_local 1)))
+)
+"#;
 
-fn maybe_main() -> Result<(), String> {
-    let data = read_to_end("test.wasm").map_err(|e| e.to_string())?;
-    let translated = translate(&data).map_err(|e| e.to_string())?;
-    let result: u32 = translated.execute_func(0, (5u32, 3u32)).unwrap();
+fn main() -> anyhow::Result<()> {
+    let data = wat::parse_str(WAT)?;
+    let translated = translate(&data)?;
+    let result: u32 = translated.execute_func(0, (5u32, 3u32))?;
     println!("f(5, 3) = {}", result);
 
     Ok(())
 }
-
-fn main() {
-    match maybe_main() {
-        Ok(()) => (),
-        Err(e) => eprintln!("error: {}", e),
-    }
-}